Copper Casting In America (Trevelyan)
Yuri Kuchinsky
Greetings, all,
Here's a brief review of a new volume about Native American
copper.
_________________
_Miskwabik, metal of ritual: metallurgy in precontact
Eastern North America_, Amelia M. Trevelyan.
Lexington : University Press of Kentucky, c2004.
("Miskwabik" is an Ojibwa word for "copper".)
Description:
Miskwabik, Metal of Ritual examines the thousands
of beautiful and intricate ritual works of art庸rom
ceremonial weaponry to delicate copper pendants
and ear ornamentså¹¼reated in eastern North
America before the arrival of Europeans. The first
comprehensive examination of this 3,000-year-old
metallurgical tradition, the book provides unique
insight into the motivation of the artisans and the
significance of these objects, and highlights the
brilliance and sophistication of the early
civilizations of the Americas. Comparing the ritual
architecture and metallurgy of the original
Americans with the ethnological record, Amelia M.
Trevelyan begins to unravel the mystery of the
significance of the objects as well as their special
functions within the societies that created them. The
book includes dozens of striking color and black
and white photographs.
Amelia M. Trevelyan is Professor and Chair of Art
History at Principia College in Elsah, Illinois.
_________________
And here's a revealing quote from the above volume, p. 15.
"Metallurgical testing and observation indicate that native
copper was primarily cold-worked in precontact times and
forged rather than cast. However, because the temperatures
necessary for melting as well as smelting copper are
comparatively low, the latter was probably a technical
possibility."
So here we see the political bias in American archaeology
laid out for all the world to see.
1. She doesn't even mention any of the available scientific
evidence indicating that, in precontact times, much copper
was cast rather than cold-worked and forged.
It may simply be plain ignorance on her part, but we
shouldn't also discount a possibility that she's
deliberately excluding any evidence that is not in accord
with her anti-Native political bias.
In any case, the name Mallory (a qualified engineer, and the
leading researcher in this area) is not mentioned in her
bibliography at all.
2. Yet she admits these things "were probably a technical
possibility". How generous of her!
So here we see the sort of an anti-Native bigotry that is
still all too common within our professional archaeological
establishment. These folks really still live in the middle
ages!
What a dark snake-pit of racism and bigotry our academic
establishment is... This never ceases to amaze me, I must
say.
This is the Dumbing-Down Crew that is hard at work to deny
the cultural achievements of Native Americans.
Regards,
Yuri.
Yuri Kuchinsky -=O=- http://www.trends.ca/~yuku
A great many people think they are thinking when they are
merely rearranging their prejudices -=O=- William James
Yuri Kuchinsky
Here's something else that I've just noted about this
subject. When I said "the Dumbing-Down Crew ... hard at
work", I was actually even more correct than I thought! :)
Yuri Kuchinsky wrote:
>
> Copper Casting In America (Trevelyan)
>
> Greetings, all,
>
> Here's a brief review of a new volume about Native American
> copper.
>
> _________________
>
> _Miskwabik, metal of ritual: metallurgy in precontact
> Eastern North America_, Amelia M. Trevelyan.
> Lexington : University Press of Kentucky, c2004.
>
> ("Miskwabik" is an Ojibwa word for "copper".)
>
> Description:
> Miskwabik, Metal of Ritual examines the thousands
> of beautiful and intricate ritual works of art -- from
> ceremonial weaponry to delicate copper pendants
> and ear ornaments -- created in eastern North
> America before the arrival of Europeans. The first
> comprehensive examination of this 3,000-year-old
> metallurgical tradition,
What's that???
"3,000-year-old metallurgical tradition,"?
Golly gee, whoever had written this blurb doesn't even know
that this metallurgical tradition is actually 5000-year-old!
What a blooper!
Page 9 of Trevelyan's own book states,
"The Old Copper Culture was a Middle to Late Archaic
development that lasted from about 3000-1000 BC, and was
focused primarily in upper Great Lakes region."
This blurb is found in a few places on the Net, for example
at,
University Press of Kentucky
http://www.kentuckypress.com/viewbook.cfm?Category_ID=14&Group=116&ID=1038
So this seems like a standard blurb.
What a bunch of turkeys... Their ignorance seems infinite.
Yuri.
Tom McDonald
Yuri,
I noticed that, too. However, the blurb isn't the book. From
the looks of things, the blooper was made by the person who
wrote the blurb, not Ms. Trevelyan.
>
> What a blooper!
>
> Page 9 of Trevelyan's own book states,
>
> "The Old Copper Culture was a Middle to Late Archaic
> development that lasted from about 3000-1000 BC, and was
> focused primarily in upper Great Lakes region."
This seems to be correct, although I would have chosen to call
it the 'Old Copper Complex'.
>
> This blurb is found in a few places on the Net, for example
> at,
>
> University Press of Kentucky
> http://www.kentuckypress.com/viewbook.cfm?Category_ID=14&Group=116&ID=1038
>
> So this seems like a standard blurb.
Might could be. The blurb is wrong; Trevelyan's text is correct.
>
> What a bunch of turkeys... Their ignorance seems infinite.
>
Maybe. But you haven't demonstrated either.
But I do thank you for pointing this book out to me.
Perhaps you could show me some of this evidence (other than the
Connor web site or the Mallery book; I can always read the
former, and have requested the latter by ILL).
>>
>>It may simply be plain ignorance on her part, but we
>>shouldn't also discount a possibility that she's
>>deliberately excluding any evidence that is not in accord
>>with her anti-Native political bias.
>>
>>In any case, the name Mallory (a qualified engineer, and the
>>leading researcher in this area) is not mentioned in her
>>bibliography at all.
Why would it be mentioned? Her book is on copper usage,
(apparently more wrt its usage as art and ceremonial usage), and
most of Mallery's book is about iron. In any case, Trevelyan
would most likely have wanted primary sources on the metallurgy,
not a book like Mallery's which quotes them.
>>
>>2. Yet she admits these things "were probably a technical
>>possibility". How generous of her!
>>
>>So here we see the sort of an anti-Native bigotry that is
>>still all too common within our professional archaeological
>>establishment. These folks really still live in the middle
>>ages!
>>
>>What a dark snake-pit of racism and bigotry our academic
>>establishment is... This never ceases to amaze me, I must
>>say.
>>
>>This is the Dumbing-Down Crew that is hard at work to deny
>>the cultural achievements of Native Americans.
Have you read the book? Or are you judging it by a
non-technical blurb and a few selected quotations? If the
former, good on ya; if the latter, then quityerbitchin until you
have.
Tom McDonald
Martyn Harrison
<yu...@trends.ca> said:
>
>Here's something else that I've just noted about this
>subject. When I said "the Dumbing-Down Crew ... hard at
>work", I was actually even more correct than I thought! :)
Bizarre for you to be correct, but yeah, you certainly are dumbing down the
subject quite considerably.
Gary Coffman
Realize that casting is primarily a technique used for cheap mass
produced items. It allows relatively low skilled workers to produce
large numbers of relatively complex identical items. Cold working is
a much more challenging, and artistically unique, way to produce
intricate copper ceremonial items. The smith has to have a higher
level of skill than the foundryman to produce equally complex work.
Given that, it seems to me that your claims of bigotry by a art
historian are unfounded. If anything, the idea that the art objects
were produced by cold work makes them even more impressive
examples of the skill of the worker than if they were mere castings.
But that said, casting pure copper is a bitch. Porosity is the enemy,
even for modern copper founders. They charge a hefty premium for
low porosity castings. Alloying the copper to make bronze improves
matters *enormously*, and production of such alloys was a huge
technological leap forward for the casting industry.
*If* the Native Americans of millenia past made the technological
leap of producing bronze alloy, it would be a significant achievement
(as it was when Old World artisans did it). But I've seen no evidence
produced in this thread that the ancient Native Americans made
such a technological leap forward.
The artifacts described appear to all be relatively pure native copper.
As such, the *intelligent* way of working the material would have
been smithing rather than casting. So if the motive were to make
ancient Native Americans appear stupid, then claiming that they
used open casting techniques would be the method of choice to do
so. Now ask yourself which side of the argument is making that
claim.
Gary
Yuri Kuchinsky
> Yuri Kuchinsky wrote:
...
> >>1. She doesn't even mention any of the available scientific
> >>evidence indicating that, in precontact times, much copper
> >>was cast rather than cold-worked and forged.
>
> Perhaps you could show me some of this evidence (other than the
> Connor web site or the Mallery book; I can always read the
> former, and have requested the latter by ILL).
The evidence is in the Mallery book, and I've already quoted
it here.
> >>It may simply be plain ignorance on her part, but we
> >>shouldn't also discount a possibility that she's
> >>deliberately excluding any evidence that is not in accord
> >>with her anti-Native political bias.
> >>
> >>In any case, the name Mallory (a qualified engineer, and the
> >>leading researcher in this area) is not mentioned in her
> >>bibliography at all.
>
> Why would it be mentioned?
Because it's relevant.
> Her book is on copper usage,
> (apparently more wrt its usage as art and ceremonial usage), and
> most of Mallery's book is about iron.
Non sequitur.
Yuri Kuchinsky
>
> On Thu, 10 Jun 2004 15:36:41 -0400, Yuri Kuchinsky <yu...@trends.ca> wrote:
> >Copper Casting In America (Trevelyan)
> >
> >Greetings, all,
> >
> >Here's a brief review of a new volume about Native American
> >copper.
> >
> >_________________
> >
> >_Miskwabik, metal of ritual: metallurgy in precontact
> >Eastern North America_, Amelia M. Trevelyan.
> >Lexington : University Press of Kentucky, c2004.
> >
> >("Miskwabik" is an Ojibwa word for "copper".)
> >
> >Description:
> >Miskwabik, Metal of Ritual examines the thousands
> >ceremonial weaponry to delicate copper pendants
Yes, Gary, but an intelligent metalworker will use the
technique that is most appropriate for the situation.
> Given that, it seems to me that your claims of bigotry by a art
> historian are unfounded. If anything, the idea that the art objects
> were produced by cold work makes them even more impressive
> examples of the skill of the worker than if they were mere castings.
It would be rather impressive if the worker knew how to use
a variety of techniques.
> But that said, casting pure copper is a bitch. Porosity is the enemy,
> even for modern copper founders. They charge a hefty premium for
> low porosity castings. Alloying the copper to make bronze improves
> matters *enormously*, and production of such alloys was a huge
> technological leap forward for the casting industry.
>
> *If* the Native Americans of millenia past made the technological
> leap of producing bronze alloy, it would be a significant achievement
> (as it was when Old World artisans did it). But I've seen no evidence
> produced in this thread that the ancient Native Americans made
> such a technological leap forward.
The Native Americans of millennia past certainly knew how to
produce bronze alloys. There's plenty of evidence of this in
S America, for example, and in Mexico.
It's also an interesting subject if the ancient Native
Americans of the Great Lakes area knew how to produce bronze
alloys. I don't exclude this possibility but, at this time,
the evidence seems to be lacking. Nobody has investigated
this possibility before, no doubt because of a racist bias
in N American archaeology.
> The artifacts described appear to all be relatively pure native copper.
> As such, the *intelligent* way of working the material would have
> been smithing rather than casting.
Not always. See above.
> So if the motive were to make
> ancient Native Americans appear stupid, then claiming that they
> used open casting techniques would be the method of choice to do
> so. Now ask yourself which side of the argument is making that
> claim.
>
> Gary
Best regards,
Yuri.
Yuri Kuchinsky -=O=- http://www.trends.ca/~yuku -=O=-
Toronto
But scientists, who ought to know
Assure us that it must be so.
Oh, let us never, never doubt
What nobody is sure about.
-- Hilaire Belloc
MIB529
Yuri Kuchinsky <yu...@trends.ca> wrote in message news:<40C8B849...@trends.ca>...
> Copper Casting In America (Trevelyan)
>
> Greetings, all,
>
> Here's a brief review of a new volume about Native American
> copper.
>
> _________________
>
> _Miskwabik, metal of ritual: metallurgy in precontact
> Eastern North America_, Amelia M. Trevelyan.
> Lexington : University Press of Kentucky, c2004.
>
> ("Miskwabik" is an Ojibwa word for "copper".)
>
> Description:
> Miskwabik, Metal of Ritual examines the thousands
> of beautiful and intricate ritual works of art?from
> ceremonial weaponry to delicate copper pendants
> and ear ornaments?created in eastern North
Seppo Renfors
Tom McDonald wrote:
>
> Yuri Kuchinsky wrote:
>
[..]
> >>1. She doesn't even mention any of the available scientific
> >>evidence indicating that, in precontact times, much copper
> >>was cast rather than cold-worked and forged.
>
> Perhaps you could show me some of this evidence (other than the
> Connor web site or the Mallery book; I can always read the
> former, and have requested the latter by ILL).
"Show me where, except the evidence of it" statement by Tom. So, if
one was to show another source than those he has excluded (which I
have done a while ago already), then he could add that to the list of
"except...", I presume!
[..]
--
SIR - Philosopher unauthorised
-----------------------------------------------------------------
The one who is educated from the wrong books is not educated, he is
misled.
-----------------------------------------------------------------
Seppo Renfors
Gary Coffman wrote:
>
> On Thu, 10 Jun 2004 15:36:41 -0400, Yuri Kuchinsky <yu...@trends.ca> wrote:
> >Copper Casting In America (Trevelyan)
[..]
> >So here we see the sort of an anti-Native bigotry that is
> >still all too common within our professional archaeological
> >establishment. These folks really still live in the middle
> >ages!
> >
> >What a dark snake-pit of racism and bigotry our academic
> >establishment is... This never ceases to amaze me, I must
> >say.
> >
> >This is the Dumbing-Down Crew that is hard at work to deny
> >the cultural achievements of Native Americans.
>
> Realize that casting is primarily a technique used for cheap mass
> produced items. It allows relatively low skilled workers to produce
> large numbers of relatively complex identical items. Cold working is
> a much more challenging, and artistically unique, way to produce
> intricate copper ceremonial items. The smith has to have a higher
> level of skill than the foundryman to produce equally complex work.
>
> Given that, it seems to me that your claims of bigotry by a art
> historian are unfounded. If anything, the idea that the art objects
> were produced by cold work makes them even more impressive
> examples of the skill of the worker than if they were mere castings.
Whilst there is little argument with that, it is still illogical to
believe that casting wasn't done. Each maker of jewellery, ceremonial
items would have ended up with "scraps" of copper. It is unlikely they
would have simply been thrown away. The annealing of copper would
bring it to melting temperature often enough for smaller thinner bits.
It suggests a very likely occurrence that they did melt copper, if for
no other reason than to make bigger pieces out of the small scraps and
off-cuts. This they would again cold work another time.
> But that said, casting pure copper is a bitch. Porosity is the enemy,
> even for modern copper founders. They charge a hefty premium for
> low porosity castings. Alloying the copper to make bronze improves
> matters *enormously*, and production of such alloys was a huge
> technological leap forward for the casting industry.
>
> *If* the Native Americans of millenia past made the technological
> leap of producing bronze alloy, it would be a significant achievement
> (as it was when Old World artisans did it). But I've seen no evidence
> produced in this thread that the ancient Native Americans made
> such a technological leap forward.
IIRC silver is found in with copper deposits in the Great Lakes area
and it has a melting point a bit lower lower than copper. It is likely
they could have used a silver/copper alloy or "bronze". If the
minerals co-exist then there is no need for "mixing", it is automatic
as with arsenic/copper deposits.
> The artifacts described appear to all be relatively pure native copper.
> As such, the *intelligent* way of working the material would have
> been smithing rather than casting. So if the motive were to make
> ancient Native Americans appear stupid, then claiming that they
> used open casting techniques would be the method of choice to do
> so. Now ask yourself which side of the argument is making that
> claim.
You see, the thing is that cold working something doesn't require
"technology", where melting/smelting does. It is the implied lack of
technology where the suggested prejudices arise from.
Gary Coffman
If they did open atmospheric casting (and I'd strongly contend they
didn't have the technology to do any other kind, nobody did until the
latter half of the 19th century, and then only as a laboratory curiosity),
the resulting copper wouldn't be suitable for cold work, too much
porosity.
Note too that the annealing temperature of copper is *way* below
the melting point. If they did melt parts of an object they were
annealing, they were using grossly too much heat. In other words,
it would be a mark of incompetence on their part if evidence of
such melting were found.
If they did attempt to salvage copper scraps, they likely *hammer
welded* them. That's done at temperatures below the melting point
of copper, so porosity doesn't become as serious a problem.
You need to understand that copper behaves *differently* from silver,
gold, or even iron. Those metals respond well to casting techniques.
Nearly pure copper does not.
(Bronze is a different matter, of course, but there still has been
no evidence presented of bronze artifacts from the locale and
period under discussion in this thread.)
>> But that said, casting pure copper is a bitch. Porosity is the enemy,
>> even for modern copper founders. They charge a hefty premium for
>> low porosity castings. Alloying the copper to make bronze improves
>> matters *enormously*, and production of such alloys was a huge
>> technological leap forward for the casting industry.
>>
>> *If* the Native Americans of millenia past made the technological
>> leap of producing bronze alloy, it would be a significant achievement
>> (as it was when Old World artisans did it). But I've seen no evidence
>> produced in this thread that the ancient Native Americans made
>> such a technological leap forward.
>
>IIRC silver is found in with copper deposits in the Great Lakes area
>and it has a melting point a bit lower lower than copper. It is likely
>they could have used a silver/copper alloy or "bronze". If the
>minerals co-exist then there is no need for "mixing", it is automatic
>as with arsenic/copper deposits.
A quick search of the UNS database doesn't show any silver-copper
binary alloy listed as suitable for casting. Nor is such a binary mixture
called bronze.
The search did turn up "nickel silver" copper alloys suitable for casting,
but the composition of those alloys *contains no silver*. They do contain
large amounts of tin, nickel, and a bit of lead. All of the binary alloys of
silver and copper listed are labeled as "wrought", meaning that they
are suitable only for cold work.
The associated native copper and silver found in the Keweenaw
Peninsula is known as "Halfbreed". It isn't even an alloy (solid
solution). It consists of intertwined gross crystals of the two
separate metals. It is difficult to produce an alloy of silver and
copper in the absence of tin.
If you heat a sample of Halfbreed, the silver melts out before
the copper reaches melting temperature, leaving a mass of
copper with voids where the silver was. It does not produce
bronze.
The presence of tin is usually, though not always (aluminum
bronze being the primary exception), a prerequisite for a
copper alloy to be called bronze. I'm unaware of any tin
deposits in the UP of Michigan.
Note, an alloy of arsenic and copper was once called bronze
too, but it is dangerous to produce, and exceedingly brittle in
use. Old World artisans very quickly abandoned it. Again, no
evidence of artifacts from the UP of Michigan composed of
that alloy has been presented.
>> The artifacts described appear to all be relatively pure native copper.
>> As such, the *intelligent* way of working the material would have
>> been smithing rather than casting. So if the motive were to make
>> ancient Native Americans appear stupid, then claiming that they
>> used open casting techniques would be the method of choice to do
>> so. Now ask yourself which side of the argument is making that
>> claim.
>
>You see, the thing is that cold working something doesn't require
>"technology", where melting/smelting does. It is the implied lack of
>technology where the suggested prejudices arise from.
Hmph! You might remember that one of the newsgroups where this
thread is appearing is the *metalworking* group. Most of the members
are machinists, either by vocation or avocation. In other words, their
primary occupation is working of metals at temperatures below the
melting point. They would *strongly* object to the notion that casting
should be the signature mark of metalworking technology.
Most of the more advanced technological working of metal is done
cold, or at least at temperatures below the melting point of the metal.
That's *particularly* true for pure copper. Most of the more astute
members would never even consider casting as a viable method for
producing pure copper objects.
Note that I am not insisting that no copper casting industry existed
in the UP of Michigan in pre-Columbian times. At least one radiograph
I've seen seems to indicate copper which had been melted in atmosphere
at some point. But what I am saying here is that atmospheric copper
casting is a particularly unintelligent way of utilizing the pure metal
when the alternative of lower temperature smithing is available.
So the apparent fact that most of the artifacts found show evidence
that they were smithed rather than cast clearly indicates that the
Native Americans were sophisticated in the working of the copper
available to them. Insisting that they cast the objects instead would
be an attempt to show that the workers were *not* sophisticated.
A very important indicator of technological sophistication is knowing
how to choose the appropriate method to work with a particular
material. In this case, the technologically appropriate method is
*not* casting. So if your objective is to minimize the technical
prowess of the Native Americans, you'd be in the camp pushing
for copper casting. Casting dumb, smithing smart.
(Again I must point out that bronze is a different matter, but no
evidence has been presented to support the production of bronze
in the locale and time under discussion.)
Gary
Gary Coffman
>Gary Coffman wrote:
>>
>> On Thu, 10 Jun 2004 15:36:41 -0400, Yuri Kuchinsky <yu...@trends.ca> wrote:
>> >Copper Casting In America (Trevelyan)
>> >What a dark snake-pit of racism and bigotry our academic
>> >establishment is... This never ceases to amaze me, I must
>> >say.
>> >
>> >This is the Dumbing-Down Crew that is hard at work to deny
>> >the cultural achievements of Native Americans.
>>
>> Realize that casting is primarily a technique used for cheap mass
>> produced items. It allows relatively low skilled workers to produce
>> large numbers of relatively complex identical items. Cold working is
>> a much more challenging, and artistically unique, way to produce
>> intricate copper ceremonial items. The smith has to have a higher
>> level of skill than the foundryman to produce equally complex work.
>
>Yes, Gary, but an intelligent metalworker will use the
>technique that is most appropriate for the situation.
Indeed! And atmospheric casting of pure native copper is *never*
the most appropriate method. Its use would be a clear indicator of
the lack of sophistication of the metalworking technology of the
people involved.
>> Given that, it seems to me that your claims of bigotry by a art
>> historian are unfounded. If anything, the idea that the art objects
>> were produced by cold work makes them even more impressive
>> examples of the skill of the worker than if they were mere castings.
>
>It would be rather impressive if the worker knew how to use
>a variety of techniques.
It is even more impressive when the worker knows enough to choose
the most appropriate technique for the material being worked. In the
case of nearly pure native copper, that technique is *not* casting.
Gary
Yuri Kuchinsky
[snip]
> Casting dumb, smithing smart.
But casting and/or smithing (depending on the materials at
hand) is more smart than just smithing.
Yuri.
Yuri Kuchinsky -=O=- http://www.trends.ca/~yuku
Students achieving Oneness will move on to Twoness.
--- W. Allen
Yuri Kuchinsky
> >Yes, Gary, but an intelligent metalworker will use the
> >technique that is most appropriate for the situation.
>
> Indeed! And atmospheric casting of pure native copper is *never*
> the most appropriate method. Its use would be a clear indicator of
> the lack of sophistication of the metalworking technology of the
> people involved.
Hmm... I wonder. Is there anyone besides yourself who thinks
so?
Yuri.
Yuri Kuchinsky -=O=- http://www.trends.ca/~yuku
Students achieving Oneness will move on to Twoness.
--- W. Allen
Tim Williams
> Hmm... I wonder. Is there anyone besides yourself who thinks
> so?
Have you personally tried casting pure copper??? Any metal for that matter?
I haven't tried copper but I imagine it isn't pretty. Unfortunately my
stock is contaminated with zinc, as I throw pennies (5% Zn) in with the pure
copper (wire, etc.) pile. ;)
Tim
--
"I've got more trophies than Wayne Gretsky and the Pope combined!"
- Homer Simpson
Website @ http://webpages.charter.net/dawill/tmoranwms
t(nospam)kavanagh
>
> "Yuri Kuchinsky" <yu...@trends.ca> wrote in message
> news:40CF635F...@trends.ca...
> > Hmm... I wonder. Is there anyone besides yourself who thinks
> > so?
>
> Have you personally tried casting pure copper??? Any metal for that matter?
Well, I for for one, while I haven't tried to cast pure copper, I did
play around with melting pennies and tin from my dad's chemistry storage
to get a nice bronze Stafforshire Knot. I have cast silver (although,
per Inger, I don't know which Indian tribe mined it:-)). Indeed the
silver belt buckle and bracelet I am wearing at the present moment I
cast in tufa, ca. 1972.
Yes, I have cast metal. Have You?
tk
Inger E Johansson
"Tim Williams" <tmor...@charter.net> skrev i meddelandet
news:10cvd7t...@corp.supernews.com...
> "Yuri Kuchinsky" <yu...@trends.ca> wrote in message
> news:40CF635F...@trends.ca...
> > Hmm... I wonder. Is there anyone besides yourself who thinks
> > so?
>
> Have you personally tried casting pure copper??? Any metal for that
matter?
>
> I haven't tried copper but I imagine it isn't pretty. Unfortunately my
> stock is contaminated with zinc, as I throw pennies (5% Zn) in with the
pure
> copper (wire, etc.) pile. ;)
I have tried copper long ago. When I was the only girl in 7th grade asking
to have metal-handicraft instead of the obligatory needlework for girls that
was one of the thing I had to learn, I also had to learn welding and of
course forging. I didn't do it much only 3 hours/week for three years.
Anyhow I can see your point Tim, but I don't agree.
Inger E
Gary Coffman
>Gary Coffman wrote:
>
>[snip]
>
>> Casting dumb, smithing smart.
>
>But casting and/or smithing (depending on the materials at
>hand) is more smart than just smithing.
True, when the material isn't pure copper. Bronze casts very
nicely, for example, as do gold, silver, iron, etc. But pure copper
doesn't. As Key to Metals says, "Pure copper is extremely difficult
to cast as well as being prone to surface cracking, porosity problems,
and to the formation of internal cavities."
Commercially, pure copper is melted and cast using a furnace
that is inert gas purged, a crushed graphite cover is floated over
the melt, and when the melt reaches 1250 C, a small amount of
calcium boride or lithium metal is injected into the melt to act
as a deoxidizer.
While silcon bronze can be successfully gravity cast in a sand
mold, pure copper cannot. Pure copper needs to be pressure
molded, either via injection or centrifugal casting methods. The
molten metal should not be exposed to air during the casting
process.
Casting pure copper is a highly sophisticated process of the
modern industrial age. The techniques to do it successfully
were only developed near the end of the 19th century when
the demand for high purity copper castings for the electrical
industry drove research and development. It is still difficult
and expensive enough to do that aluminum, brass, or bronze
is substituted for pure copper wherever it is practical to do so
in electrical equipment.
Gary
Doug Weller
> Gary Coffman wrote:
>
> [snip]
>
>> Casting dumb, smithing smart.
>
> But casting and/or smithing (depending on the materials at
> hand) is more smart than just smithing.
Yuri has me killfiled so may not see this, but I am fed up with his going
on about 'smart' and 'dumbing down'. It takes more than intelligence to
develop technologies, and the lack of a technology does not mean that a
group of people are 'dumb'. To say that Native Americans did not develop
electricity, nuclear power, or various types of metalworking does *not*
mean that they are dumb. And it doesn't make the person making the
statement racist.
This is basically just Yuri's need to cast nasturtiums at scholars, this
time archaeologists. He does the same thing with Biblical scholars in other
newsgroups.
Doug
Gary Coffman
I picked up on the fact that he was more interested in axe grinding than
casting.
Gary
Yuri Kuchinsky
Hi, Gary,
My main interest in all this is to investigate Native
American history.
There are apparently hundreds if not thousands of
pre-historic metal furnaces that have been described all
over northern US. So it sure looks like the Native Americans
must have been smelting or melting something. Probably
copper, iron, maybe bronze.
Some non-professional archaeologists have investigated these
things, and published their findings.
I find these things quite fascinating. And yet professional
American archaeologists don't seem to show any interest at
all. They insist on looking the other way. Why do you think
this is so?
Regards,
Yuri.
Yuri Kuchinsky -=O=- http://www.trends.ca/~yuku
Reality is that which, when you stop believing
in it, doesn't go away -=O=- Philip K. Dick
Seppo Renfors
I agree that is most likely to have been the procedure. On the other
hand what we don't really know is if the porosity was a problem for
them.
>
> Note too that the annealing temperature of copper is *way* below
> the melting point. If they did melt parts of an object they were
> annealing, they were using grossly too much heat. In other words,
> it would be a mark of incompetence on their part if evidence of
> such melting were found.
I suspect you are using modern ideas as a guide, knowing of other
techniques etc. Back then in learning about melting copper, they must
observe it melt. Learning annealing they again need to observe the
effects, thereby also learning to heat to just below melting point and
lend itself to the "hammer welding" you refer to below.
> If they did attempt to salvage copper scraps, they likely *hammer
> welded* them. That's done at temperatures below the melting point
> of copper, so porosity doesn't become as serious a problem.
....and it would also eliminate porosity, would it not? So the small
bit could well be melted and cast into a small ingot - to later
"hammer weld" the porosity out of it.
> You need to understand that copper behaves *differently* from silver,
> gold, or even iron. Those metals respond well to casting techniques.
> Nearly pure copper does not.
I'm aware of the difficulty - as well as the evidence it provides of
casting. As such evidence does exist, even if not widely, it indicates
the ability to melt copper.
>
> (Bronze is a different matter, of course, but there still has been
> no evidence presented of bronze artifacts from the locale and
> period under discussion in this thread.)
>
> >> But that said, casting pure copper is a bitch. Porosity is the enemy,
> >> even for modern copper founders. They charge a hefty premium for
> >> low porosity castings. Alloying the copper to make bronze improves
> >> matters *enormously*, and production of such alloys was a huge
> >> technological leap forward for the casting industry.
> >>
> >> *If* the Native Americans of millenia past made the technological
> >> leap of producing bronze alloy, it would be a significant achievement
> >> (as it was when Old World artisans did it). But I've seen no evidence
> >> produced in this thread that the ancient Native Americans made
> >> such a technological leap forward.
> >
> >IIRC silver is found in with copper deposits in the Great Lakes area
> >and it has a melting point a bit lower lower than copper. It is likely
> >they could have used a silver/copper alloy or "bronze". If the
> >minerals co-exist then there is no need for "mixing", it is automatic
> >as with arsenic/copper deposits.
>
> A quick search of the UNS database doesn't show any silver-copper
> binary alloy listed as suitable for casting.
Try the old 3 cent piece - it was silver + copper alloy. Nor does it
need to be "fit for casting" in the modern sense, as all I see it used
for is to generate a larger lump of material to work with as a smith
would.
> Nor is such a binary mixture called bronze.
A copper alloy is in general called "bronze" irrespective of the mix
(eg arsenic + copper) except when it is called "brass" (nickle +
copper?).
> The search did turn up "nickel silver" copper alloys suitable for casting,
> but the composition of those alloys *contains no silver*. They do contain
> large amounts of tin, nickel, and a bit of lead. All of the binary alloys of
> silver and copper listed are labeled as "wrought", meaning that they
> are suitable only for cold work.
>
> The associated native copper and silver found in the Keweenaw
> Peninsula is known as "Halfbreed". It isn't even an alloy (solid
> solution). It consists of intertwined gross crystals of the two
> separate metals. It is difficult to produce an alloy of silver and
> copper in the absence of tin.
No, it has been done a lot of the time. In Sweden (damn I lost the
info tag..) they have something they call "malm" (ore) that is a
bronze, but a far redder colour than normal bronze. I can't tell you
the mix of it as I lost the info. However there is a lot of arsenic +
copper bronze around in Asia Minor. It was mined in the Ural mountains
as a ready mixed ore.
>
> If you heat a sample of Halfbreed, the silver melts out before
> the copper reaches melting temperature, leaving a mass of
> copper with voids where the silver was. It does not produce
> bronze.
It does if you heat it to the melting point of copper.
http://ia.essortment.com/threecentcoin_rlzk.htm
> The presence of tin is usually, though not always (aluminum
> bronze being the primary exception), a prerequisite for a
> copper alloy to be called bronze. I'm unaware of any tin
> deposits in the UP of Michigan.
Tin is indeed the most common, but not the sole mix.
>
> Note, an alloy of arsenic and copper was once called bronze
> too, but it is dangerous to produce, and exceedingly brittle in
> use. Old World artisans very quickly abandoned it. Again, no
> evidence of artifacts from the UP of Michigan composed of
> that alloy has been presented.
It is still called "bronze" as the "bronze age" term itself says.
>
> >> The artifacts described appear to all be relatively pure native copper.
> >> As such, the *intelligent* way of working the material would have
> >> been smithing rather than casting. So if the motive were to make
> >> ancient Native Americans appear stupid, then claiming that they
> >> used open casting techniques would be the method of choice to do
> >> so. Now ask yourself which side of the argument is making that
> >> claim.
> >
> >You see, the thing is that cold working something doesn't require
> >"technology", where melting/smelting does. It is the implied lack of
> >technology where the suggested prejudices arise from.
>
> Hmph! You might remember that one of the newsgroups where this
> thread is appearing is the *metalworking* group. Most of the members
> are machinists, either by vocation or avocation. In other words, their
> primary occupation is working of metals at temperatures below the
> melting point. They would *strongly* object to the notion that casting
> should be the signature mark of metalworking technology.
Ahhh.... but irrespective of the fact that artisans may get their nose
out of joint, melting/smelting metals IS called a "technology". So
having that technology under ones belt in addition to the smithing, is
indeed one up on the smithing alone :-)
> Most of the more advanced technological working of metal is done
> cold, or at least at temperatures below the melting point of the metal.
> That's *particularly* true for pure copper. Most of the more astute
> members would never even consider casting as a viable method for
> producing pure copper objects.
Not suggesting modern people do cast copper - I am saying ancient
people did.
> Note that I am not insisting that no copper casting industry existed
> in the UP of Michigan in pre-Columbian times. At least one radiograph
> I've seen seems to indicate copper which had been melted in atmosphere
> at some point. But what I am saying here is that atmospheric copper
> casting is a particularly unintelligent way of utilizing the pure metal
> when the alternative of lower temperature smithing is available.
While there is/was almost pure copper available at the time, much of
it had impurities embedded within it. Large hunks of pure copper were
relatively rare. The vast amounts that are indicated to have been
mined must include copper with much impurities or copper embedded in
other material. This had to be refined somehow, melting is the
simplest way of refining it - unless you know of another technique
available to the ancients.
> So the apparent fact that most of the artifacts found show evidence
> that they were smithed rather than cast clearly indicates that the
> Native Americans were sophisticated in the working of the copper
> available to them. Insisting that they cast the objects instead would
> be an attempt to show that the workers were *not* sophisticated.
Nobody is suggesting that smithing isn't an extremely skilled
occupation..... but then so is flint knapping in my view. The casting
was not used to manufacture anything much apparently. I see it as a
refining process to later be hammered at near melting temperatures,
thereby producing fine artefacts.
> A very important indicator of technological sophistication is knowing
> how to choose the appropriate method to work with a particular
> material. In this case, the technologically appropriate method is
> *not* casting. So if your objective is to minimize the technical
> prowess of the Native Americans, you'd be in the camp pushing
> for copper casting. Casting dumb, smithing smart.
As I said mastering one technology, is less than mastering TWO
technologies.... if you want to call smithing a "technology" in favour
of Art :-)
>
> (Again I must point out that bronze is a different matter, but no
> evidence has been presented to support the production of bronze
> in the locale and time under discussion.)
I don't know what if any testing of composition of artefacts has been
done. Some bronzes only contain 3 -> 5% tin elsewhere. If none are
done then a claim that bronze doesn't exist can't be made. Testing the
metals would also finger print them for origin, which hasn't been done
either to my knowledge.
Inger E Johansson
"Yuri Kuchinsky" <yu...@trends.ca> skrev i meddelandet
news:40D3150F...@trends.ca...
copper yes, bronze yes, silver yes(to pour in forms) but not iron. That they
didn't do until they began trading silver, furs and eagles with the Norse
according to the oral tradition I have had from respected Indians I spoken
to.
Inger E
Martin H. Eastburn
>
> Gary Coffman wrote:
>
>>On Tue, 15 Jun 2004 05:29:28 GMT, Seppo Renfors <Ren...@not.net.au> wrote:
>>
>>>Gary Coffman wrote:
>>>
>>>>On Thu, 10 Jun 2004 15:36:41 -0400, Yuri Kuchinsky <yu...@trends.ca> wrote:
>>>>
>>>>>Copper Casting In America (Trevelyan)
>>>
Considering copper :
1. find some rich ore or native or near native.
2. build one hot fire - continue burning and increase coal / charcoal contents.
3. add copper or ore - perhaps using glass technology of the time - pit glass ?
more melted stone that is glassy and use this slab as a cookie sheet . :-)
4. cover the top with more fuel and then cap it off - perhaps air vent on the
side of the wind...
A reduction fire - and when cooled off it might have metal in the sheet...
Maybe.
Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer old...@pacbell.net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder
Eric Stevens
wrote:
With respect, that is nonsense. Casting is a technique which is used
to make shapes and structures which cannot be easily made any other
way.
>It allows relatively low skilled workers to produce
>large numbers of relatively complex identical items.
You do them a disservice to describe them as "low skilled". The work
is difficult and dnagerous, and it took centuries to develop the
techniques.
>Cold working is
>a much more challenging, and artistically unique, way to produce
>intricate copper ceremonial items. The smith has to have a higher
>level of skill than the foundryman to produce equally complex work.
Which is why the people who know how to melt and cast copper use that
technique rather than straight smith-work.
>
>Given that, it seems to me that your claims of bigotry by a art
>historian are unfounded. If anything, the idea that the art objects
>were produced by cold work makes them even more impressive
>examples of the skill of the worker than if they were mere castings.
I think you are missing the point, and so too may be the art
historian. There seems to be evidence that some copper items were
cast. From what I have read, the cast products would not generally
qualify as 'art' and for that reason have understandably been ignored
by art historians.
>
>But that said, casting pure copper is a bitch.
This from the guy who has just written that the task can be undertaken
by low-skilled workers?
>Porosity is the enemy,
>even for modern copper founders. They charge a hefty premium for
>low porosity castings. Alloying the copper to make bronze improves
>matters *enormously*, and production of such alloys was a huge
>technological leap forward for the casting industry.
>
>*If* the Native Americans of millenia past made the technological
>leap of producing bronze alloy, it would be a significant achievement
>(as it was when Old World artisans did it). But I've seen no evidence
>produced in this thread that the ancient Native Americans made
>such a technological leap forward.
>
>The artifacts described appear to all be relatively pure native copper.
>As such, the *intelligent* way of working the material would have
>been smithing rather than casting. So if the motive were to make
>ancient Native Americans appear stupid, then claiming that they
>used open casting techniques would be the method of choice to do
>so. Now ask yourself which side of the argument is making that
>claim.
Neither. The claim merely is that some copper items have been cast.
Eric Stevens
Tom McDonald
> On Fri, 11 Jun 2004 22:57:04 GMT, ke...@bellsouth.net (Gary Coffman)
> wrote:
<snip>
>>Realize that casting is primarily a technique used for cheap mass
>>produced items.
>
>
> With respect, that is nonsense. Casting is a technique which is used
> to make shapes and structures which cannot be easily made any other
> way.
Eric,
In the case of the copper artifacts in the upper Great Lakes
area, all of the shapes and structures have been shown to have
been made via cold and hot-working techniques. (Note that I am
not saying that all the copper artifacts were so made; only that
casting was not necessary.) As for whether certain types of
tools and ornaments might be more easily made by casting, this
is only true if the technology for casting has been developed.
That is what is at issue.
>
>
>>It allows relatively low skilled workers to produce
>>large numbers of relatively complex identical items.
>
>
> You do them a disservice to describe them as "low skilled". The work
> is difficult and dnagerous, and it took centuries to develop the
> techniques.
Yes, especially wrt copper (see Gary's discussion of copper
casting problems below). So far as I can see at this point,
there isn't good evidence for such a period of development in
the archaeological record.
OTOH, at least for the Old Copper and Red Ochre complexes in
the Upper Great Lakes region, there don't seem to be many
well-documented sites from that period (ca. 3000-1000 BC); and
stratified sites are even more rare. Most of the copper
artifacts were surface finds, and many came from collectors
whose documentation of their finds generally ranged from fair to
non-existent.
>
>
>>Cold working is
>>a much more challenging, and artistically unique, way to produce
>>intricate copper ceremonial items. The smith has to have a higher
>>level of skill than the foundryman to produce equally complex work.
>
>
> Which is why the people who know how to melt and cast copper use that
> technique rather than straight smith-work.
Again, I don't know that that is true wrt copper, given the
difficulty the technique appears to have in creating strong,
high-quality results. OTOH, cold and hot working were known by
the Native peoples in the Great Lakes ares to produce that very
strong, high-quality result.
<snip>
>>But that said, casting pure copper is a bitch.
>
>
> This from the guy who has just written that the task can be undertaken
> by low-skilled workers?
Eric, I read that to mean that casting, in general (as with
iron, silver, bronze, gold, etc.) can be done by folks with
fewer skills than smiths. However, copper appears to present
particular problems with casting that are not so pronounced with
other metals, and which require higher skill levels than would
be required by those who cast other metals.
This should be taken into consideration along with the fact
that Great Lakes copper, and drift copper, don't need to be
smelted to use. In other areas, where smelting ore _is_
required, the technology for melting metal is a given; here, it
isn't.
>
>
>>Porosity is the enemy,
>>even for modern copper founders. They charge a hefty premium for
>>low porosity castings. Alloying the copper to make bronze improves
>>matters *enormously*, and production of such alloys was a huge
>>technological leap forward for the casting industry.
>>
>>*If* the Native Americans of millenia past made the technological
>>leap of producing bronze alloy, it would be a significant achievement
>>(as it was when Old World artisans did it). But I've seen no evidence
>>produced in this thread that the ancient Native Americans made
>>such a technological leap forward.
>>
>>The artifacts described appear to all be relatively pure native copper.
>>As such, the *intelligent* way of working the material would have
>>been smithing rather than casting. So if the motive were to make
>>ancient Native Americans appear stupid, then claiming that they
>>used open casting techniques would be the method of choice to do
>>so. Now ask yourself which side of the argument is making that
>>claim.
>
>
> Neither. The claim merely is that some copper items have been cast.
Eric, Yuri was making the claim that to say Indians of the
Great Lakes area didn't cast copper was to express bigotry
towards the First Nations of the area. Gary's argument flows
from Yuri's standard 'mainstreamers are racists' rap, with its
particular application in the cast vs. worked copper issue.
I'm still agnostic, and am reading up on the archaeological
references I can find. If you, or other folks, have suggestions
for reading, I'm all eyes.
BTW, I've just gotten Mallery's book (the 1979 version, revised
and extended by Mary Roberts Harrison). I've only skimmed a bit
of it, so I don't have an informed opinion on it yet. Will advise.
Tom McDonald
Eric Stevens
<tmcdon...@charter.net> wrote:
>Eric Stevens wrote:
>
>> On Fri, 11 Jun 2004 22:57:04 GMT, ke...@bellsouth.net (Gary Coffman)
>> wrote:
>
><snip>
>
>>>Realize that casting is primarily a technique used for cheap mass
>>>produced items.
>>
>>
>> With respect, that is nonsense. Casting is a technique which is used
>> to make shapes and structures which cannot be easily made any other
>> way.
>
>Eric,
>
> In the case of the copper artifacts in the upper Great Lakes
>area, all of the shapes and structures have been shown to have
>been made via cold and hot-working techniques.
This is not my understanding. Metallurgical examination has shown that
some of the artifacts have been cast.
>(Note that I am
>not saying that all the copper artifacts were so made; only that
>casting was not necessary.)
That seems to be a different topic. Are you saying that even if they
were found to be cast, it wasn't necessary for them to be cast?
> As for whether certain types of
>tools and ornaments might be more easily made by casting, this
>is only true if the technology for casting has been developed.
>That is what is at issue.
I think you and I are approaching the question from opposite ends. You
seem to be saying that no artifacts can have been cast, in the absence
of direct evidence for casting techniques. I am saying that cast
artifacts are evidence for the existence of casting techniques, even
if direct evidence for such techniques is not known.
I don't read 'low skilled' as meaning 'lower skilled'.
>
> This should be taken into consideration along with the fact
>that Great Lakes copper, and drift copper, don't need to be
>smelted to use. In other areas, where smelting ore _is_
>required, the technology for melting metal is a given; here, it
>isn't.
There is a difference between 'smelted' as in refinining and 'melted'
as for casting. I am not aware of evidence for the for the former in
NA but there may be evidence for the latter in the form of cast
artifacts.
Very much the curate's egg.
Eric Stevens
Tom McDonald
> On Wed, 23 Jun 2004 23:46:01 -0500, Tom McDonald
> <tmcdon...@charter.net> wrote:
>
>
>>Eric Stevens wrote:
>>
>>
>>>On Fri, 11 Jun 2004 22:57:04 GMT, ke...@bellsouth.net (Gary Coffman)
>>>wrote:
>>
>><snip>
>>
>>>>Realize that casting is primarily a technique used for cheap mass
>>>>produced items.
>>>
>>>
>>>With respect, that is nonsense. Casting is a technique which is used
>>>to make shapes and structures which cannot be easily made any other
>>>way.
>>
>>Eric,
>>
>> In the case of the copper artifacts in the upper Great Lakes
>>area, all of the shapes and structures have been shown to have
>>been made via cold and hot-working techniques.
>
>
> This is not my understanding. Metallurgical examination has shown that
> some of the artifacts have been cast.
Eric,
That could be. That's why I wrote the below.
My point here is that at least two researchers have done
experiments using only cold and hot working, without casting,
making all of the major types of artifacts found in the Great
Lakes area. This is not to say that some might not have been
cast. That's the issue. Contrary to what you write above, I
have not yet completed my own look into whether some might have
been cast. I'm not willing to take at face value reports of
research the originals of which I haven't yet found.
>
>
>>(Note that I am
>>not saying that all the copper artifacts were so made; only that
>>casting was not necessary.)
>
>
> That seems to be a different topic. Are you saying that even if they
> were found to be cast, it wasn't necessary for them to be cast?
It's the same topic. I was trying to avoid just this confusion
by stating frankly that the research I mentioned does not rule
out casting. And to your question, yes. I'm saying that it
seems to me at this point that both casting and smithing could
have produced the tools we find. The issue is whether both
techniques were used, and if so over what time period and what
places within the region.
>
>
>>As for whether certain types of
>>tools and ornaments might be more easily made by casting, this
>>is only true if the technology for casting has been developed.
>>That is what is at issue.
>
>
> I think you and I are approaching the question from opposite ends. You
> seem to be saying that no artifacts can have been cast, in the absence
> of direct evidence for casting techniques. I am saying that cast
> artifacts are evidence for the existence of casting techniques, even
> if direct evidence for such techniques is not known.
You mistake my meaning. I am saying that casting and smithing
both could have been used. If there are artifacts that were
cast, then that fact should inform future archaeological work.
I'm not sure that you know this, but the main copper-using
cultures of the upper Great Lakes areas are very poorly
represented by habitation sites. In Wisconsin and the UP of
Michigan, there are only a few such sites that have been found
and studied from this period (Late Archaic to the transition to
Early Woodland--ca. 3-4000 to ca. 100 BC).
There are a great many sites with copper artifacts, but they
are mostly either surface finds, or are in mortuary contexts;
not where the ancient smiths/foundryfolk might have been
expected to ply their trades
I am less sanguine than you that old reports for which we have
only second-hand sources, and for which we don't know the
caveats and limitations of the researchers, can be accepted
uncritically in the face of nearly unanimous statement from
those who have studied the copper artifacts intensively that
they haven't found convincing evidence of casting. However, I
take offense at the suggestion that I've ruled out casting when
I am actually looking into the issue with an open mind.
Read it again. No mention of 'low skilled'. Merely that a
smith needs 'higher level of skill' than a foundryman. A
neurosurgeon may need a 'higher level of skill' than a
dermatologist. Does this make the dermatologist 'low skilled'?q
>
>> This should be taken into consideration along with the fact
>>that Great Lakes copper, and drift copper, don't need to be
>>smelted to use. In other areas, where smelting ore _is_
>>required, the technology for melting metal is a given; here, it
>>isn't.
>
>
> There is a difference between 'smelted' as in refinining and 'melted'
> as for casting. I am not aware of evidence for the for the former in
> NA but there may be evidence for the latter in the form of cast
> artifacts.
Of course smelting ore and melting for casting are different.
However, if one needs and has the technology for smelting,
melting for casting is not a technological leap. If one does
not need to smelt ore, then melting it for casting requires that
technological leap. The issue is whether that leap was made in
this case. If cast artifacts are found, then looking for
evidence of the development of that technology would be a higher
archaeological priority than it is now.
I'm not familiar with that. Will you explain for me?
Tom McDonald
Eric Stevens
<tmcdon...@charter.net> wrote:
Fair enough. You may remember that some years ago I reported that I
had tried to track down Mallery's papers (left to the Smithsonian on
his death) to obtain copies of the originals upon which he relied, but
all the papers seem to have vanished into a black hole. It might be
worth another try.
>
>>
>>
>>>(Note that I am
>>>not saying that all the copper artifacts were so made; only that
>>>casting was not necessary.)
>>
>>
>> That seems to be a different topic. Are you saying that even if they
>> were found to be cast, it wasn't necessary for them to be cast?
>
> It's the same topic. I was trying to avoid just this confusion
>by stating frankly that the research I mentioned does not rule
>out casting. And to your question, yes. I'm saying that it
>seems to me at this point that both casting and smithing could
>have produced the tools we find.
Only if your assessment is based on simplistic visual examination.
Appropriate metallurgical tests are unambiguous.
I didn't say, or even imply, that you have unconditionally ruled out
the possibility of cast artifacts.
Gary Coffman originally wrote of casting "It allows relatively low
skilled workers to produce ... " and it was to this which I originally
repsonded. My point was that casting is not a low skilled technique.
>Merely that a
>smith needs 'higher level of skill' than a foundryman. A
>neurosurgeon may need a 'higher level of skill' than a
>dermatologist. Does this make the dermatologist 'low skilled'?q
But is the fundamental proposition correct, that a dermatologist is
necessarily of lower skill than a neurosurgeon? My observation is that
while the disciplines are different, the skill levels are equally high
in each.
>
>>
>>> This should be taken into consideration along with the fact
>>>that Great Lakes copper, and drift copper, don't need to be
>>>smelted to use. In other areas, where smelting ore _is_
>>>required, the technology for melting metal is a given; here, it
>>>isn't.
>>
>>
>> There is a difference between 'smelted' as in refinining and 'melted'
>> as for casting. I am not aware of evidence for the for the former in
>> NA but there may be evidence for the latter in the form of cast
>> artifacts.
>
> Of course smelting ore and melting for casting are different.
>However, if one needs and has the technology for smelting,
>melting for casting is not a technological leap. If one does
>not need to smelt ore, then melting it for casting requires that
>technological leap. The issue is whether that leap was made in
>this case.
The discovery of either smelting or melting would initially be
accidental. I could think of circumstances in which melting could
still occur when working with pure meteoric copper.
>If cast artifacts are found, then looking for
>evidence of the development of that technology would be a higher
>archaeological priority than it is now.
I do not share your certainty. Cast artifacts do seem to have been
found. I am not aware that the reports cited by Mallery have been
followed up in any way. As far as I can tell, nobody has even followed
them up for the purpose of showing that they were wrong or that
Mallery has misinterpreted them. The whole subject seems to have been
treated as a non-issue.
A 19th century 'Punch' cartoon. The very new curate is having
breakfast with his bishop and finds the boiled egg he has been served
is rotten. The curate lacks the courage to complain about the bishop's
breakfast fodder but the expression on his face alerts the bishop to
the fact that all is not well. The bishop then asks ' ... and how is
your egg?' The curate still too nervous to say the egg is rotten
replies "Parts of it are excellent, my lord". That last is the comment
I applied to Mallery's book.
Eric Stevens
Eric Stevens
<eric.s...@sum.co.nz> wrote:
>>> Very much the curate's egg.
>>
>> I'm not familiar with that. Will you explain for me?
>>
>A 19th century 'Punch' cartoon. The very new curate is having
>breakfast with his bishop and finds the boiled egg he has been served
>is rotten. The curate lacks the courage to complain about the bishop's
>breakfast fodder but the expression on his face alerts the bishop to
>the fact that all is not well. The bishop then asks ' ... and how is
>your egg?' The curate still too nervous to say the egg is rotten
>replies "Parts of it are excellent, my lord". That last is the comment
>I applied to Mallery's book.
>
http://www.quinion.com/words/qa/qa-cur1.htm gives an even better
explanation.
Eric Stevens
Inger E Johansson
"Eric Stevens" <eric.s...@sum.co.nz> skrev i meddelandet
news:bevpd055646if54nt...@4ax.com...
Eric,
I thought I told you last summer that Mallery's paper is found in a Private
Museum? Didn't you get any of the files I have from the Keller deposit? I am
sure we discussed photos taken of the artifacts.
Inger E
Eric Stevens
<inger_e....@notelia.com> wrote:
>
>"Eric Stevens" <eric.s...@sum.co.nz> skrev i meddelandet
>news:bevpd055646if54nt...@4ax.com...
>> On Fri, 25 Jun 2004 19:24:15 -0500, Tom McDonald
>> <tmcdon...@charter.net> wrote:
>>
>> >Eric Stevens wrote:
>> >
>> >> On Wed, 23 Jun 2004 23:46:01 -0500, Tom McDonald
>> >> <tmcdon...@charter.net> wrote:
--- snip ---
>> > That could be. That's why I wrote the below.
>> >
>> > My point here is that at least two researchers have done
>> >experiments using only cold and hot working, without casting,
>> >making all of the major types of artifacts found in the Great
>> >Lakes area. This is not to say that some might not have been
>> >cast. That's the issue. Contrary to what you write above, I
>> >have not yet completed my own look into whether some might have
>> >been cast. I'm not willing to take at face value reports of
>> >research the originals of which I haven't yet found.
>>
>> Fair enough. You may remember that some years ago I reported that I
>> had tried to track down Mallery's papers (left to the Smithsonian on
>> his death) to obtain copies of the originals upon which he relied, but
>> all the papers seem to have vanished into a black hole. It might be
>> worth another try.
>
>Eric,
>I thought I told you last summer that Mallery's paper is found in a Private
>Museum? Didn't you get any of the files I have from the Keller deposit? I am
>sure we discussed photos taken of the artifacts.
All that I can find which might possibly relate to that is "Shipley,
Marie A. [Brown]. The Norse Colonization in America by the Light of
the Vatican Finds. Lucerne: H. Keller's Foreign Printing Office,
[1899]."
It doesn't seem to relate to Mallery in any way.
--- snip ----
Eric Stevens
Inger E Johansson
It must either have been eaten of your computer when it was sent to service
or been sent via the one of telia's servers which has had problems sending
files to Australia and New Zealand.
I do have a lot of info. I am writing on a thriller for the moment, together
with an old friend of mine. Thus I can't put it in my computer before
midnight Swedish time when I am home after we have gone thru some of the
chapters in the book. You will have the first files tomorrow.
Inger E
George
> >
> >
> > All that I can find which might possibly relate to that is "Shipley,
> > Marie A. [Brown]. The Norse Colonization in America by the Light of
> > the Vatican Finds. Lucerne: H. Keller's Foreign Printing Office,
> > [1899]."
> >
> > It doesn't seem to relate to Mallery in any way.
>
> It must either have been eaten of your computer when it was sent to service
> or been sent via the one of telia's servers which has had problems sending
> files to Australia and New Zealand.
hey Eric dont you let that one go by. Start Inger off on an A+ course
> I do have a lot of info. I am writing on a thriller for the moment, together
> with an old friend of mine. Thus I can't put it in my computer before
> midnight Swedish time when I am home after we have gone thru some of the
> chapters in the book. You will have the first files tomorrow.
>
Hey what number excuse are we up to here?
Is the klock still running
Gary Coffman
>Gary Coffman wrote:
>> If they did open atmospheric casting (and I'd strongly contend they
>> didn't have the technology to do any other kind, nobody did until the
>> latter half of the 19th century, and then only as a laboratory curiosity),
>> the resulting copper wouldn't be suitable for cold work, too much
>> porosity.
>
>I agree that is most likely to have been the procedure. On the other
>hand what we don't really know is if the porosity was a problem for
>them.
It would be a problem, a big problem.
>> If they did attempt to salvage copper scraps, they likely *hammer
>> welded* them. That's done at temperatures below the melting point
>> of copper, so porosity doesn't become as serious a problem.
>
>....and it would also eliminate porosity, would it not? So the small
>bit could well be melted and cast into a small ingot - to later
>"hammer weld" the porosity out of it.
No, it couldn't. Porosity isn't just little bubbles in the metal. Those
bubbles contain air, and at molten temperatures, the oxygen in that
air would oxidize the inside of the bubble. So what you wind up with is
a mass of copper with a lot of oxidized holes in it. You can't weld
copper that is oxidized. If this happens when a modern TIG welder
is welding copper (gas shield failure), the only thing he can do is
grind out all the porosity and start over.
>> You need to understand that copper behaves *differently* from silver,
>> gold, or even iron. Those metals respond well to casting techniques.
>> Nearly pure copper does not.
>
>I'm aware of the difficulty - as well as the evidence it provides of
>casting. As such evidence does exist, even if not widely, it indicates
>the ability to melt copper.
No trick to melting copper. Doing something intelligent with the molten
metal in an atmospheric environment is a different matter. As I noted
previously, casting pure copper is difficult, even today. For a people
without inert gas shielded continuous casting furnaces, it would be
nothing but frustration.
Gary
Gary Coffman
>> On Fri, 11 Jun 2004 22:57:04 GMT, ke...@bellsouth.net (Gary Coffman)
>> wrote:
>>>But that said, casting pure copper is a bitch.
>>
>>
>> This from the guy who has just written that the task can be undertaken
>> by low-skilled workers?
>
> Eric, I read that to mean that casting, in general (as with
>iron, silver, bronze, gold, etc.) can be done by folks with
>fewer skills than smiths. However, copper appears to present
>particular problems with casting that are not so pronounced with
> other metals, and which require higher skill levels than would
>be required by those who cast other metals.
Exactly, and further, skill alone isn't sufficient to make sound
castings of pure copper. The proper equipment is also required.
Specifically, an inert atmosphere furnace. That technology
didn't exist until the late 19th century.
Gary
Gary Coffman
>On Wed, 23 Jun 2004 23:46:01 -0500, Tom McDonald
><tmcdon...@charter.net> wrote:
>> In the case of the copper artifacts in the upper Great Lakes
>>area, all of the shapes and structures have been shown to have
>>been made via cold and hot-working techniques.
>
>This is not my understanding. Metallurgical examination has shown that
>some of the artifacts have been cast.
The evidence brought out in this thread is that *one* copper artifact
shows radiographic evidence (characteristic porosity) for part of it
being heated above the melting point in atmosphere at some point.
That is in no way conclusive evidence of casting technology. The
piece may have been an attempt at casting, or it may simply have
been overheated while being worked.
Gary
Tom McDonald
Gary,
Are you referring to the sort of amorphous, three-cornered blob
listed in Conner's web site as 'R666', and in the Milwaukee
Public Museum (where it's curated) as '55786':
http://www.iwaynet.net/~wdc/copper.htm
If so, I have found additional information about that piece.
Tom McDonald
Gary Coffman
>Gary Coffman wrote:
>> The evidence brought out in this thread is that *one* copper artifact
>> shows radiographic evidence (characteristic porosity) for part of it
>> being heated above the melting point in atmosphere at some point.
>> That is in no way conclusive evidence of casting technology. The
>> piece may have been an attempt at casting, or it may simply have
>> been overheated while being worked.
>>
>> Gary
>
>Gary,
>
> Are you referring to the sort of amorphous, three-cornered blob
>listed in Conner's web site as 'R666', and in the Milwaukee
>Public Museum (where it's curated) as '55786':
>
>http://www.iwaynet.net/~wdc/copper.htm
>
> If so, I have found additional information about that piece.
>
>Tom McDonald
Yes, that's the one. What have you learned?
Gary
Tom McDonald
Gary,
I corresponded with Dr. Alex Barker of the Milwaukee Public
Museum about this artifact, since they are curating it there.
His response about the description of the artifact was as follows:
"As to why one might wonder if it had been cast, it's relatively
dense for its size, and one surface is fairly smooth and
rounded--not like the upper surface of cast metal, however, but
one might perhaps imagine it as the bottom of an irregular
puddle of metal."
It sounded to me as though he had just looked at it; he was
more than generous with me, running around and looking for the
artifact and associated documentation for me. Unfortunately, he
says he couldn't find a record of any radiograph, but that that
didn't mean it wasn't there. They are changing their records
over to computer files, and the integration of those files won't
start for several months yet. I for one don't doubt the
radiographs shown on Connor's web site, though.
The description he gave seems to fit the photo on Connor's
site. It doesn't look like any purpose-made artifact; but it
does look as one might expect a bit of accidentally melted
copper to look, if it just fell into the ashes of the fire and
cooled there. To my untutored eye, at least.
Tom McDonald
Eric Stevens
wrote:
But the question is, how pure was the copper.
In any case, copper can mostly by prevented from oxidising by melting
it under a layer of crushed coal or charcoal. In fact this method was
used for the production of largely deoxised (tough-pitch) copper in
recent time.
>For a people
>without inert gas shielded continuous casting furnaces, it would be
>nothing but frustration.
>
Don't under rate the cunning of anceint man.
Eric Stevens
Eric Stevens
wrote:
>On Sat, 26 Jun 2004 11:13:49 +1200, Eric Stevens <eric.s...@sum.co.nz> wrote:
Maybe you missed it but http://www.iwaynet.com/~wdc/copper.htm was
cited a few weeks ago in sci.archaeology and introduces evidence for
the casting of copper. Arlington Mallery's book gives more details
including the results of competent metallurgical examination.
Eric Stevens
Eric Stevens
wrote:
>On Wed, 23 Jun 2004 23:46:01 -0500, Tom McDonald <tmcdon...@charter.net> wrote:
Just as well the ancient egyptians didn't know that they couldn't do
what they were doing. :-)
Eric Stevens
Gary Coffman
So, are you claiming to have evidence that the ancient Egyptians
successfully cast pure native copper?
The metallurgical references I have say that native copper was
extremely rare in Egypt. Almost all of the copper they had was
refined from ores (smelted), and the results were *not* pure
copper. Rather, they were alloys, whether intentional or not,
of copper, arsenic, zinc, iron, or tin. These alloys behave *very*
differently from pure native copper when casting is attempted.
Gary
Gary Coffman
No, I didn't miss it. That's where the reference to artifact R666 was
found. None of the other artifacts shown present convincing evidence
(characteristic porosity) of having been poured in atmosphere.
Gary
Gary Coffman
>Gary Coffman wrote:
>> On Sun, 27 Jun 2004 13:18:58 -0500, Tom McDonald <tmcdon...@charter.net> wrote:
>>>Gary Coffman wrote:
>>>>The evidence brought out in this thread is that *one* copper artifact
>>>>shows radiographic evidence (characteristic porosity) for part of it
>>>>being heated above the melting point in atmosphere at some point.
>>>>That is in no way conclusive evidence of casting technology. The
>>>>piece may have been an attempt at casting, or it may simply have
>>>>been overheated while being worked.
>>>
>>>listed in Conner's web site as 'R666', and in the Milwaukee
>>>Public Museum (where it's curated) as '55786':
>>>
>>>http://www.iwaynet.net/~wdc/copper.htm
>>>
>>> If so, I have found additional information about that piece.
>>
>
>Museum about this artifact, since they are curating it there.
>His response about the description of the artifact was as follows:
>
>"As to why one might wonder if it had been cast, it's relatively
>dense for its size, and one surface is fairly smooth and
>rounded--not like the upper surface of cast metal, however, but
>one might perhaps imagine it as the bottom of an irregular
>puddle of metal."
Interesting that he'd characterize it as "relatively dense for its size".
The density measurement reported on the web site says it is less
dense than ordinary native copper (8.2 vs 8.9). That's consistent
with the porosity shown in the radiograph.
I suspect that Dr Barker has neither metallurgical nor geological
training. So his density report is just that of a layman picking up
a hunk of metal. But if I'm wrong in that supposition, then he is
contradicting the information provided on the web site.
> The description he gave seems to fit the photo on Connor's
>site. It doesn't look like any purpose-made artifact; but it
>does look as one might expect a bit of accidentally melted
>copper to look, if it just fell into the ashes of the fire and
>cooled there. To my untutored eye, at least.
That would be significant in itself. The heat required to melt
such a mass of copper can't be produced in an ordinary open
wood fire. A forced draft fire burning a high carbon fuel such
as charcoal or actual metallurgical grade coal would normally
be required to supply the heat necessary to melt that mass.
Now that's consistent with a smith's forge or a casting furnace.
It isn't consistent with an ordinary wood fire used to anneal
worked native copper. So that lends support to the thesis that
the ancient Native Americans controlled such a high temperature
technology.
OTOH, a forest fire can produce sufficient natural draft to reach
the required temperature. So it is *possible* that R666 was in
such a natural fire. That would explain what we see in the radiograph
without the necessity of claiming high temperature technology for
the ancient Native Americans.
The fact that we have only one artifact showing the characteristic
porosity we'd expect from native copper melted in atmosphere
lends credence to the latter hypothesis. If we saw a *lot* of artifacts
from different locations showing characteristic porosity, that'd be
another story. But no good evidence has been presented to support
that, certainly not the other examples on the web site. The radiographs
of other items on the site are more consistent with wrought items
than cast items.
As I mentioned previously, surface blisters are not what we're
looking for in terms of the porosity characteristic of pure copper
casting. What we need to see is a foam of microscopic bubbles,
and clusters of tiny visible bubbles deep in the metal on the
radiographs. That's absent from the other radiographs on the
site.
Gary
Tom McDonald
Gary,
He has a background in anthropology, so I wouldn't expect that
he would necessarily have much in the way of metallurgical
training, and his geology might be limited. As you noted, his
observation on the heaviness of the object seemed to belie
amateur status in those fields.
I'm not arguing about the details reported in Conner's web
site. I'm just concerned that his and his sources may have gone
beyond the evidence in certain cases.
>
>
>> The description he gave seems to fit the photo on Connor's
>>site. It doesn't look like any purpose-made artifact; but it
>>does look as one might expect a bit of accidentally melted
>>copper to look, if it just fell into the ashes of the fire and
>>cooled there. To my untutored eye, at least.
>
>
> That would be significant in itself. The heat required to melt
> such a mass of copper can't be produced in an ordinary open
> wood fire. A forced draft fire burning a high carbon fuel such
> as charcoal or actual metallurgical grade coal would normally
> be required to supply the heat necessary to melt that mass.
>
> Now that's consistent with a smith's forge or a casting furnace.
> It isn't consistent with an ordinary wood fire used to anneal
> worked native copper. So that lends support to the thesis that
> the ancient Native Americans controlled such a high temperature
> technology.
>
> OTOH, a forest fire can produce sufficient natural draft to reach
> the required temperature. So it is *possible* that R666 was in
> such a natural fire. That would explain what we see in the radiograph
> without the necessity of claiming high temperature technology for
> the ancient Native Americans.
I'm getting around to reading two detailed archaeological
reports on the Riverside site, as well as a short report on
mortuary issues at the site written by Lewis Binford. You have
helped me frame some key questions to keep in mind when reading
them. In addition to the obvious (copper artifacts and
cremation details), you've got me looking for localized,
atypical hearths and discussions about charcoal and/or ash that
might be from forest fires instead of controlled hearth or
cremation fires. Thanks.
>
> The fact that we have only one artifact showing the characteristic
> porosity we'd expect from native copper melted in atmosphere
> lends credence to the latter hypothesis. If we saw a *lot* of artifacts
> from different locations showing characteristic porosity, that'd be
> another story. But no good evidence has been presented to support
> that, certainly not the other examples on the web site. The radiographs
> of other items on the site are more consistent with wrought items
> than cast items.
What strikes me about the copper blob we're discussing is that
if it were to have been overpour or other waste from a casting
event, I'd expect it to have been added to a 'try again' pile,
to be melted with other smaller bits for later casting. Of
course, it could have just been forgotten. I'll have to look in
the reports for indications of ceramics, with a specific concern
for what might have been used as crucibles.
>
> As I mentioned previously, surface blisters are not what we're
> looking for in terms of the porosity characteristic of pure copper
> casting. What we need to see is a foam of microscopic bubbles,
> and clusters of tiny visible bubbles deep in the metal on the
> radiographs. That's absent from the other radiographs on the
> site.
Yes, that's why I was interested in your take on R666/55786.
If there were other good examples of melted copper, I'd have
expected that the web site would have presented them. As it is,
it looks as though I'll have to dig for other examples that
might show casting.
Tom McDonald
Eric Stevens
wrote:
Did you see my Message-ID:
<9in5b01qe7ofj7725...@4ax.com> in which I quote
metallurgical aspects from Mallery?
Eric Stevens
Eric Stevens
wrote:
Apart from the fact that it all depends what you mean by 'pure', yes,
I have read to that effect.
>
>The metallurgical references I have say that native copper was
>extremely rare in Egypt. Almost all of the copper they had was
>refined from ores (smelted), and the results were *not* pure
>copper. Rather, they were alloys, whether intentional or not,
>of copper, arsenic, zinc, iron, or tin. These alloys behave *very*
>differently from pure native copper when casting is attempted.
While not directly addressing the point, you may be interested in
http://www.lehigh.edu/~inarcmet/papers/jfa022002.pdf
Eric Stevens
Inger E Johansson
"Tom McDonald" <tmcdon...@charter.net> skrev i meddelandet
news:10dv19q...@corp.supernews.com...
If I remember it correctly, saw a report at my friend's house the other day,
it was in an Ohio site such was found or at least ceramics found was
believed to have been used as crucibles.
Inger E
Gary Coffman
>On Sun, 27 Jun 2004 02:58:26 -0400, Gary Coffman <ke...@bellsouth.net>
>wrote:
>>metal in an atmospheric environment is a different matter. As I noted
>>previously, casting pure copper is difficult, even today.
>
>But the question is, how pure was the copper.
The native copper we've been discussing is very high purity.
The halfbreed ore does contain silver, but the silver isn't in
solid solution with the copper (copper-silver alloys are difficult
to produce). Instead it is in the form of distinct crystal inclusions
which would melt out and separate before the copper would melt.
>In any case, copper can mostly by prevented from oxidising by melting
>it under a layer of crushed coal or charcoal. In fact this method was
>used for the production of largely deoxised (tough-pitch) copper in
>recent time.
A graphite cover was used to prevent oxidation while melting (coal
won't work because of the large fraction of volatiles, charcoal might
be useable). But you also have to deal with the air entrained when
pouring.
A bottom pour furnace is helpful, but you really need deoxidizers in
the alloy to prevent severe porosity problems. Tin and zinc are the
preferred deoxidizers. Arsenic also works, but the fumes are deadly.
Lead makes the metal more fluid, and assists in filling out the mold.
None of those are naturally present in the native copper we're
discussing.
Also, as a side note, where is the evidence for coal mining or large
scale charcoal production in the area? You don't get to copper
melting temperatures with a simple wood fire. You need a forced
draft fire with a high carbon fuel.
>>For a people
>>without inert gas shielded continuous casting furnaces, it would be
>>nothing but frustration.
>>
>
>Don't under rate the cunning of anceint man.
Don't underestimate the difficulty of getting sound pure copper
castings. Low alloy bronzes and brasses (approx 0.5% to 1% tin
or zinc respectively) aren't too bad to cast, high alloy bronzes
and brasses are easy. But casting pure copper is hard, even
with today's technology.
Again, porosity is the problem, and that should show up on
radiographs, as it does for R666 (which certainly shows evidence
of being melted in atmosphere, though not necessarily evidence
of being cast), but none of the other artifacts presented show
that sort of porosity.
I believe we are agreed that only atmospheric casting was within
reach of the ancient Native Americans (or ancient Old World
founders for that matter), so we *should* see characteristic
porosity in any pure copper items they attempted to cast. Now
of course the Old Worlders had the advantage of ores which
did contain suitable deoxidizers. They weren't actually casting
pure copper. But the Michigan copper was essentially pure
native copper.
Gary
Gary Coffman
>If I remember it correctly, saw a report at my friend's house the other day,
>it was in an Ohio site such was found or at least ceramics found was
>believed to have been used as crucibles.
What I've seen since I started looking into this is a report of a purported
ceramic mold fragment discovered in Ohio. However, there is considerable
disagreement as to whether that actually is a mold fragment or not. It is
also far from the native copper sites being discussed, and hasn't been
dated to the time frame under discussion. So it sheds very little light on
the subject of pure copper casting.
Gary
Gary Coffman
While not Egyptian, and the artifacts analyzed show evidence of
being wrought rather than cast, the chemical analysis does back
my position. The metals being worked were alloys, not pure native
copper.
Gary
Tom McDonald
> "Tom McDonald" <tmcdon...@charter.net> skrev i meddelandet
> news:10dv19q...@corp.supernews.com...
<snip>
>>What strikes me about the copper blob we're discussing is that
>>if it were to have been overpour or other waste from a casting
>>event, I'd expect it to have been added to a 'try again' pile,
>>to be melted with other smaller bits for later casting. Of
>>course, it could have just been forgotten. I'll have to look in
>>the reports for indications of ceramics, with a specific concern
>>for what might have been used as crucibles.
>
>
> If I remember it correctly, saw a report at my friend's house the other day,
> it was in an Ohio site such was found or at least ceramics found was
> believed to have been used as crucibles.
>
> Inger E
Inger,
I'd like to have information about that site in Ohio. I'm
especially interested in:
Date(s) and culture(s) of the ceramics;
Reports and photos about the potential crucibles;
Location(s) of the find(s);
References to work on the artifacts, and/or primary
investigator(s) on the studies.
Thanks.
Tom McDonald
Yuri Kuchinsky
Well, Gary, the folowing sure seems to imply that the
ancient Egyptian did some copper casting.
[quote]
Ancient Egyptian raw materials: metals - copper, bronze,
iron, gold, silver, lead
http://nefertiti.iwebland.com/trades/metals.htm
Re: copper objects [rather than bronze]:
The objects were generally cast, which is quite difficult to
do with copper because of the formation of gas bubbles
during the pouring of the metal and its shrinking when it
cooled down. Then they were hammered cold to give them their
final form.
[unquote]
Yuri.
Yuri Kuchinsky -=O=- http://www.trends.ca/~yuku
Reality is that which, when you stop believing
in it, doesn't go away -=O=- Philip K. Dick
Yuri Kuchinsky
Hi, Gary,
Here you seem to be implying that copper casting wasn't done
in the ancient world at all.
You couldn't be more wrong, my friend... Sure seems to me
like you're not very knowledgeable about the ways that the
ancient peoples worked with metals.
And this implies that your general knowledge about
metalworking is rather deficient, since you've reached the
above conclusion based on it, rather than on your
familiarity with archaeological evidence.
So here's some archaeological evidence for a change, that
refutes your speculations about the ancient peoples not
casting pure copper.
[quotes]
INDIA
http://www.hindunet.org/hindu_history/sarasvati/html/artefacts.htm
Melting of native copper was done by putting the regulus
[lump of copper] over furnace or fire in a crucible and then
casting it.
IRELAND
Copper and Tin Mining in Ireland in the Bronze Age
http://www.thecelticplanet.com/mining.htm
It is estimated that in the early Bronze Age in Ireland, not
more than 14% of artifacts were of bronze. The remainder
were made from copper only
SOUTHERN SIBERIA
http://faculty.web.waseda.ac.jp/yukis/sougen13.mei.html
Intriguingly, the majority of cauldrons recovered in
southern Siberia were also made of pure copper instead of
tin bronze. According to Bogdanova-Berezobskaya (1963: 136,
153), among the twenty cauldrons analyzed, thirteen are pure
copper, five arsenical copper (As 1-1.5%), one tin bronze,
and one Cu-Sn-Pb alloy.
[the date range above seems to be 7th-8th centuries BC]
http://www.thecopperlink.com/products/copper-timeless/history-of/pr_co-ti_hi-of_index.php
the oldest artefacts are not made of copper tin alloys, they
are made of pure copper.
Some examples of early smelted copper artefacts:
-- 3800 BC Spatula, Chisel, Awl - Iran (Yahya)
-- 3500 BC Flat axe - Egypt
[end quotes]
So it's never too late to educate yourself about such
things, Gary.
Best regards,
Tom McDonald
Yuri,
Your site tells us that copper ore was what was available, not
native copper; and that it had to be smelted before use. IOW,
it's not clear whether the Egyptians ever had copper of the
purity of the native copper in the upper Great Lakes area. In
addition, the smelting and melting of that copper would more
than likely have resulted in a copper alloy, not pure copper.
Of course, if you have better evidence that shows Egyptians
cast 99+% pure copper, you are welcome to present it here. I
for one would be very interested in that evidence.
Tom McDonald
Eric Stevens
wrote:
As I said, it all depends upon what you mean by 'pure'.
Eric Stevens
Eric Stevens
wrote:
>On Mon, 28 Jun 2004 08:52:10 +1200, Eric Stevens <eric.s...@sum.co.nz> wrote:
>>On Sun, 27 Jun 2004 02:58:26 -0400, Gary Coffman <ke...@bellsouth.net>
>>wrote:
>>>No trick to melting copper. Doing something intelligent with the molten
>>>metal in an atmospheric environment is a different matter. As I noted
>>>previously, casting pure copper is difficult, even today.
>>
>>But the question is, how pure was the copper.
>
>The native copper we've been discussing is very high purity.
>The halfbreed ore does contain silver, but the silver isn't in
>solid solution with the copper (copper-silver alloys are difficult
>to produce). Instead it is in the form of distinct crystal inclusions
>which would melt out and separate before the copper would melt.
>
>>In any case, copper can mostly by prevented from oxidising by melting
>>it under a layer of crushed coal or charcoal. In fact this method was
>>used for the production of largely deoxised (tough-pitch) copper in
>>recent time.
>
>A graphite cover was used to prevent oxidation while melting (coal
>won't work because of the large fraction of volatiles, charcoal might
>be useable). But you also have to deal with the air entrained when
>pouring.
Here is a quote from 'Metallurgy for Engineers' Rollason, 2nd Edition,
first published 1939:
Begin quote:
---------------------------------
Production of Tough Pitch Copper. In fire-refining copper the
impurities are removed by oxidising the metal until about 4 per cent
copper oxide (Cu20) is absorbed. During this stage the impurities form
oxides more readily than the copper and are removed as a slag or
evolved as gas. The last impurity so removed is sulphur which is not
completely driven off as sulphur dioxide by mere oxidation, but to
remove the last traces the metal has to be violently agitated by
poling, i.e. introducing an unseasoned piece of wood under the
surface. This causes a miniature fountain of molten copper, and allows
the air to come into contact with the spraying metal. Small test
castings or button castings are taken to indicate the state of the
metal. With sulphur present the ingot spurts just as it goes solid due
to the evolution of gas (SO2), but as the sulphur is reduced in amount
the surface of the ingot sinks in the manner normal to most metals. If
a micro-examination is made of this metal it will be found to contain
globules of copper oxide in the form of a eutectic (Cu-Cu2O). A layer
of crushed coal is then placed on the molten copper, and as poling
continues the copper oxide is reduced and when a content of about 0.04
to 0.08 per cent oxygen is reached the surface of the button remains
level and the properties of the metal are good, in other words
"tough." The lower the oxygen, the higher the so-called "pitch" and
vice versa, hence the name "Tough Pitch." As poling continues past
this point the copper absorbs hydrogen from the furnace gases and when
cast the metal rises on solidification.
These changes in behaviour, micro-structure and mechanical properties
are due to the influence of hydrogen and oxygen on the copper.
----------------------------------------
End quote
The above confirms not only the use of crushed coal but also the
primitive nature of the processes by means of which relatively pure
copper was produced even in the 20th century. Stirring with a piece of
unseasoned wood is a practice which may have roots going back for
millenia.
My point is that our ancestors have had a habit of producing materials
with primitive techniques which we have now largely forgotten about.
The fact the we now do things only with modern gizmos doen't mean that
our ancestors couldn't do much the same thing some other way.
>
>A bottom pour furnace is helpful, but you really need deoxidizers in
>the alloy to prevent severe porosity problems. Tin and zinc are the
>preferred deoxidizers. Arsenic also works, but the fumes are deadly.
>Lead makes the metal more fluid, and assists in filling out the mold.
>None of those are naturally present in the native copper we're
>discussing.
>
>Also, as a side note, where is the evidence for coal mining or large
>scale charcoal production in the area? You don't get to copper
>melting temperatures with a simple wood fire. You need a forced
>draft fire with a high carbon fuel.
A good bed of well ventilated charcoal will suffice. One often finds
melted copper in the remains of burned out buildings.
>
>>>For a people
>>>without inert gas shielded continuous casting furnaces, it would be
>>>nothing but frustration.
>>>
>>
>>Don't under rate the cunning of anceint man.
>
>Don't underestimate the difficulty of getting sound pure copper
>castings. Low alloy bronzes and brasses (approx 0.5% to 1% tin
>or zinc respectively) aren't too bad to cast, high alloy bronzes
>and brasses are easy. But casting pure copper is hard, even
>with today's technology.
Once again, it depends what you mean by pure. Somewhere I have seen
reference to a recognised ancient copper alloy containing 0.5% As
which was produced by addition of the As. Clearly they were able to
produce copper with less than that level of As.
>
>Again, porosity is the problem, and that should show up on
>radiographs, as it does for R666 (which certainly shows evidence
>of being melted in atmosphere, though not necessarily evidence
>of being cast), but none of the other artifacts presented show
>that sort of porosity.
>
>I believe we are agreed that only atmospheric casting was within
>reach of the ancient Native Americans (or ancient Old World
>founders for that matter), so we *should* see characteristic
>porosity in any pure copper items they attempted to cast.
Only if they used the relatively pure meteoric copper of Michigan. It
was laikely to be naturally alloyed if it was smelted.
>Now
>of course the Old Worlders had the advantage of ores which
>did contain suitable deoxidizers. They weren't actually casting
>pure copper. But the Michigan copper was essentially pure
>native copper.
>
But it wasn't the only source of copper.
Eric Stevens
Tom McDonald
Eric,
In the context of this thread, at least its original context,
the copper was native copper in the upper Great Lakes area of
the US and Canada. That copper is typically well over 99% pure
out of the ground, and does not have to be smelted to remove
impurities. If another context is in evidence, then a
definition of the term 'pure' is needed.
In the cases Yuri noted (e.g.: Egypt, Harrapa, China), that
copper was apparently smelted from ore, and analysis of
individual artifacts would be necessary to describe the ratio of
copper to alloy materials. In one of Yuri's examples, 'pure'
copper artifacts were all below 98.8% copper.
I agree, therefore, that one cannot take a statement that some
artifact or artifact type was 'pure copper' at face value. It
needs to be quantified.
Tom McDonald
Tom McDonald
> On Mon, 28 Jun 2004 13:07:35 -0400, Gary Coffman <ke...@bellsouth.net>
> wrote:
<snip>
>>Now
>>of course the Old Worlders had the advantage of ores which
>>did contain suitable deoxidizers. They weren't actually casting
>>pure copper. But the Michigan copper was essentially pure
>>native copper.
>>
>
> But it wasn't the only source of copper.
Eric,
This thread began, and has mostly developed, around that
Michigan (with some from Wisconsin and Minnesota) native copper,
more specifically its use in the upper Great Lakes area.
Yuri has begun a thread about copper casting outside of this
area. Perhaps that would be a better venue for this more
general discussion of ancient copper.
Tom McDonald
Gary Coffman
The quote is a procedure for smelting chalcopyrite ore. That's a very
different procedure from what is required to process pure native copper.
Apples and oranges.
>>A bottom pour furnace is helpful, but you really need deoxidizers in
>>the alloy to prevent severe porosity problems. Tin and zinc are the
>>preferred deoxidizers. Arsenic also works, but the fumes are deadly.
>>Lead makes the metal more fluid, and assists in filling out the mold.
>>None of those are naturally present in the native copper we're
>>discussing.
>>
>>Also, as a side note, where is the evidence for coal mining or large
>>scale charcoal production in the area? You don't get to copper
>>melting temperatures with a simple wood fire. You need a forced
>>draft fire with a high carbon fuel.
>
>A good bed of well ventilated charcoal will suffice. One often finds
>melted copper in the remains of burned out buildings.
A fully engulfed large building, or a forest fire, can produce sufficient
natural draft to reach copper melting temperature, but you'd need a
forced draft for a simple bed of charcoal. For doing very small amounts
of metal, such as small silver jewelry items, blowpipes would suffice, but
for doing anything on the order of the size of the artifacts we've been
examining, a bellows or blower would be required, and a *lot* of charcoal.
Let me propose that you conduct an experiment. Go to your local "high
end" audio shop and purchase some oxygen free copper "monster" wire
(similar properties to native copper). Now try to melt it in your backyard
barbeque. The insulation will burn off, but I'll be very surprised if you can
get the wire to melt without a forced air draft and *several* loads of
charcoal.
Making charcoal is an industrial enterprise in itself. I'm asking is there
any evidence of such activity in the area under discussion? So far I
have seen no reference to such activities. Nor have I seen any reference
to coal mining activity in the area. All that has been reported is mining
of native copper deposits.
>>I believe we are agreed that only atmospheric casting was within
>>reach of the ancient Native Americans (or ancient Old World
>>founders for that matter), so we *should* see characteristic
>>porosity in any pure copper items they attempted to cast.
>
>Only if they used the relatively pure meteoric copper of Michigan. It
>was laikely to be naturally alloyed if it was smelted.
Meteoric copper? Perhaps you're thinking of iron. The copper we're
discussing is native copper. Native copper is the result of a natural
geochemical leaching process in certain types of rock formations.
It results in extremely high purity copper.
>>Now
>>of course the Old Worlders had the advantage of ores which
>>did contain suitable deoxidizers. They weren't actually casting
>>pure copper. But the Michigan copper was essentially pure
>>native copper.
>>
>But it wasn't the only source of copper.
True, there are impure ores present in the region as well. But
there is absolutely no evidence that any of it was mined or
processed prior to the latter part of the 19th century. Further,
the impure ores which are present contain iron and sulphur
as their major contaminants. Those impurities are extremely
undesireable in copper that is to be cast. The ore has to be
smelted to remove those impurities.
No significant amounts of tin, zinc, arsenic, or lead, which
would improve casting qualities, are present in the ores of
the region. So even if the ancients had adulterated their
native copper with these ores, the result would not be an
improvement in the ability to cast objects from the resultant
mixture.
The ancients lacked a scientific understanding of metallurgy,
but they weren't stupid. They proceded by a sequence of trial
and error steps. If they added something, and the result was
worse, they'd quickly understand not to do that again. Since
the Native Americans in Michigan already had access to very
high purity native copper, and any local adulterant they added
would only make its properties worse, I'd suggest that they
quickly learned not to add any adulterants.
Now the situation was different in the Old World. The metalworkers
there had access to adulterants which *would* improve the casting
properties of copper, and they fairly quickly learned to add such
materials to their copper. That's not because they were brighter,
it is simply because they had materials at hand which weren't
available to the ancients of Michigan.
Gary
Paul K. Dickman
Tom McDonald wrote in message <10e15kl...@corp.supernews.com>...
>Eric,
>
> In the context of this thread, at least its original context,
>the copper was native copper in the upper Great Lakes area of
>the US and Canada. That copper is typically well over 99% pure
>out of the ground, and does not have to be smelted to remove
>impurities. If another context is in evidence, then a
>definition of the term 'pure' is needed.
>
> In the cases Yuri noted (e.g.: Egypt, Harrapa, China), that
>copper was apparently smelted from ore, and analysis of
>individual artifacts would be necessary to describe the ratio of
>copper to alloy materials. In one of Yuri's examples, 'pure'
>copper artifacts were all below 98.8% copper.
>
> I agree, therefore, that one cannot take a statement that some
>artifact or artifact type was 'pure copper' at face value. It
>needs to be quantified.
>
>Tom McDonald
Much has been bandied about concerning the purity of the copper from the UP,
but you must realize that the same geological process that separates the
copper also separates several other metals at the same time. It does not
place them miles apart but leaves the next to each other, fractions of a
millimeter apart.
for some clarification we will define some vocabulary.
Native copper
This is copper that was left in it's metallic state by the process that
concentrated it. It can be loose, or they can be stuck in a hunk of matrix
exactly as they came out of the ground with other native metals in close
proximity.
Drift copper
This is native copper that has been pounded from its matrix by glacial
action.
Placer deposit
This is a deposit of native metal that has been removed from it's matrix
by erosion (glacial or otherwise) moved from it's original location (usually
by wind or water) and, by nature of its specific gravity and it's resistance
to the motive force has been concentrate with other bits of metal with like
characteristics.
The native copper of the UP is unusually pure. This does not, however, mean
that every piece of rock with copper in it contains only copper.
Below is snip from a site about gold mining in the UP.
.http://www.geo.msu.edu/geo333/gold.html
In June the following year(1846), Houghton’s younger brother Jacob, found a
vein of native copper on the Keweenaw Peninsula which held a small amount of
gold. An assay yielded 10.25 ounces of copper, 1.75 ounces of silver and 12
grains of gold from the 28-ounce specimen
You can see that this particular sample was nearly 15% silver!
Drift copper has had most of the other materials removed by mechanical
action and is usually very pure.
The specific gravities of silver, copper etc. are actually quite close when
compared to sand and placer deposits may contain these in any mix.
Now as to melting.
These native metals are melted for one of three basic reasons.
One, to change it's shape to a finished product
Even today, casting generally produces products that are inferior to
wrought. It is only used when the form cannot economically be produced any
other way,
It is fairly difficult with pure copper, and frankly, if you found a 3
lb hunk of drift copper you would be better off pounding it to shape.
Two, to amalgamate several smaller pieces into one or more larger ones.
The purpose of this is not ,necessarily, to produce a finished product,
but to produce an ingot . Despite copper's casting difficulties, we have
managed to pour ingots of it for almost as long as we have worked metals.
The beauty of the ingot is that if you make it big enough, you can cut
off the bad parts, melt them into the next ingot and pound the rest into
whatever you want.
However, since parent metal is no longer a single nugget of pure copper,
the purity of the casting can be anything.
Three, to separate the metals from the matrix.
This too produces a fine ingot and in the case of Mr. Houghton's sample,
one with 15% silver .
Paul K. DIckman
Eric Stevens
wrote:
I don't know where you get that from. The opening sentence says very
clearly "In fire-refining copper ... ".
>That's a very
>different procedure from what is required to process pure native copper.
>Apples and oranges.
But then that's not why I quoted the article. I did so to deal with
your rebuttal of the use of a layer of coal to prevent oxidisation.
>
>>>A bottom pour furnace is helpful, but you really need deoxidizers in
>>>the alloy to prevent severe porosity problems. Tin and zinc are the
>>>preferred deoxidizers. Arsenic also works, but the fumes are deadly.
>>>Lead makes the metal more fluid, and assists in filling out the mold.
>>>None of those are naturally present in the native copper we're
>>>discussing.
>>>
>>>Also, as a side note, where is the evidence for coal mining or large
>>>scale charcoal production in the area? You don't get to copper
>>>melting temperatures with a simple wood fire. You need a forced
>>>draft fire with a high carbon fuel.
>>
>>A good bed of well ventilated charcoal will suffice. One often finds
>>melted copper in the remains of burned out buildings.
>
>A fully engulfed large building, or a forest fire, can produce sufficient
>natural draft to reach copper melting temperature, but you'd need a
>forced draft for a simple bed of charcoal. For doing very small amounts
>of metal, such as small silver jewelry items, blowpipes would suffice, but
>for doing anything on the order of the size of the artifacts we've been
>examining, a bellows or blower would be required, and a *lot* of charcoal.
>
>Let me propose that you conduct an experiment. Go to your local "high
>end" audio shop and purchase some oxygen free copper "monster" wire
>(similar properties to native copper). Now try to melt it in your backyard
>barbeque. The insulation will burn off, but I'll be very surprised if you can
>get the wire to melt without a forced air draft and *several* loads of
>charcoal.
Actually I have carried out that very experiment to replicate damage
seen to 'Monster cable' in a domestic fire. Just for the heck of it I
through some into the base of a Jotul Alpha wood stove. The monster
cable variously melted or sintered into a solid bar of copper. FYI,
the Jotul Alpha is an 'air-tight' stove with the only air entry being
down the face of the front door glass from the top.
>
>Making charcoal is an industrial enterprise in itself. I'm asking is there
>any evidence of such activity in the area under discussion? So far I
>have seen no reference to such activities. Nor have I seen any reference
>to coal mining activity in the area. All that has been reported is mining
>of native copper deposits.
That's a very different question from the use of coal to prevent
oxidisation.
>
>>>I believe we are agreed that only atmospheric casting was within
>>>reach of the ancient Native Americans (or ancient Old World
>>>founders for that matter), so we *should* see characteristic
>>>porosity in any pure copper items they attempted to cast.
>>
>>Only if they used the relatively pure meteoric copper of Michigan. It
>>was laikely to be naturally alloyed if it was smelted.
>
>Meteoric copper? Perhaps you're thinking of iron.
Its a term used to describe the copper deposited by contact with
meteoric water. Meteoric water is ground water formed by
precipitation. See
http://www.minsocam.org/MSA/collectors_corner/vft/mi2c.htm
>The copper we're
>discussing is native copper. Native copper is the result of a natural
>geochemical leaching process in certain types of rock formations.
>It results in extremely high purity copper.
Only in some places.
Eric Stevens
Tom McDonald
Paul,
I'm getting a good free education in this copper business. I
thank you and Gary for your tutelage.
I don't recall reading anything about, for instance, silver
artifacts in the upper Great Lakes area; but this doesn't mean
it wasn't used. I rather suspect that folks were breaking rocks
to extract copper, and may have discarded as debitage the
non-copper bits.
I'll have to look into this, as it would seem that silver might
have been present in large enough amounts that it might have
wound up in archaeological contexts. And, of course, when white
folks came later to investigate and further exploit some of the
copper deposits, I'd be surprised if any silver were to have
been ignored by them.
Tom McDonald
Seppo Renfors
See:
http://www.iwaynet.net/~wdc/copper.htm
The 4th and 5th pictures down.
> I believe we are agreed that only atmospheric casting was within
> reach of the ancient Native Americans (or ancient Old World
> founders for that matter), so we *should* see characteristic
> porosity in any pure copper items they attempted to cast. Now
> of course the Old Worlders had the advantage of ores which
> did contain suitable deoxidizers. They weren't actually casting
> pure copper. But the Michigan copper was essentially pure
> native copper.
Isn't it just possible that you focus too strongly on perfect casting
- the imperfections resulting from casting may not have been a real
big deal to the ancient people.
--
SIR - Philosopher unauthorised
-----------------------------------------------------------------
The one who is educated from the wrong books is not educated, he is
misled.
-----------------------------------------------------------------
Seppo Renfors
Tom McDonald wrote:
>
> Gary Coffman wrote:
>
[..]
> > As I mentioned previously, surface blisters are not what we're
> > looking for in terms of the porosity characteristic of pure copper
> > casting. What we need to see is a foam of microscopic bubbles,
> > and clusters of tiny visible bubbles deep in the metal on the
> > radiographs. That's absent from the other radiographs on the
> > site.
>
> Yes, that's why I was interested in your take on R666/55786.
> If there were other good examples of melted copper, I'd have
> expected that the web site would have presented them.
IT DOES!! It has been pointed to several times already. Your recent
posting is regurgitating what you have posted before. An apparent
casual visual inspection by the Museum curator, nothing more. Here is
the URL again - and don't forget to scroll down a bit!!
http://www.iwaynet.net/~wdc/copper.htm
> As it is,
> it looks as though I'll have to dig for other examples that
> might show casting.
Listen if the seriousness of your "looking" is equal to your looking
on the web site - give it a miss. You wouldn't see anything anyway.
Seppo Renfors
Tom McDonald wrote:
>
> Eric Stevens wrote:
>
> > On Mon, 28 Jun 2004 13:22:35 -0400, Gary Coffman <ke...@bellsouth.net>
> > wrote:
> >
> >
> >>On Mon, 28 Jun 2004 17:38:04 +1200, Eric Stevens <eric.s...@sum.co.nz> wrote:
[..]
> >>>While not directly addressing the point, you may be interested in
> >>>http://www.lehigh.edu/~inarcmet/papers/jfa022002.pdf
> >>
> >>While not Egyptian, and the artifacts analyzed show evidence of
> >>being wrought rather than cast, the chemical analysis does back
> >>my position. The metals being worked were alloys, not pure native
> >>copper.
> >
> >
> > As I said, it all depends upon what you mean by 'pure'.
>
> Eric,
>
> In the context of this thread, at least its original context,
> the copper was native copper in the upper Great Lakes area of
> the US and Canada. That copper is typically well over 99% pure
> out of the ground, and does not have to be smelted to remove
> impurities. If another context is in evidence, then a
> definition of the term 'pure' is needed.
http://www.dayooper.com/Networks.JPG
The copper may well be 99% pure - what about the rest? It isn't every
day people find huge lumps of pure copper without impurities embedded
within it. This is the dilemma that people bypass and ignore.
This has a good story about the Great lakes Copper deposits.
http://www.geo.msu.edu/geo333/copper.html
[..]
Gary Coffman
>Gary Coffman wrote:
>> Don't underestimate the difficulty of getting sound pure copper
>> castings. Low alloy bronzes and brasses (approx 0.5% to 1% tin
>> or zinc respectively) aren't too bad to cast, high alloy bronzes
>> and brasses are easy. But casting pure copper is hard, even
>> with today's technology.
>>
>> Again, porosity is the problem, and that should show up on
>> radiographs, as it does for R666 (which certainly shows evidence
>> of being melted in atmosphere, though not necessarily evidence
>> of being cast), but none of the other artifacts presented show
>> that sort of porosity.
>
>See:
>http://www.iwaynet.net/~wdc/copper.htm
>
>The 4th and 5th pictures down.
Those pictures do not show any evidence of the characteristic
porosity copper casting would produce. The single large surface
bubble is a blister, common when the surface of a wrought piece
is overheated. Compare it to the radiograph of R666. The latter
does show the characteristic deep pattern of porosity of an at least
partially melted copper object.
>> I believe we are agreed that only atmospheric casting was within
>> reach of the ancient Native Americans (or ancient Old World
>> founders for that matter), so we *should* see characteristic
>> porosity in any pure copper items they attempted to cast. Now
>> of course the Old Worlders had the advantage of ores which
>> did contain suitable deoxidizers. They weren't actually casting
>> pure copper. But the Michigan copper was essentially pure
>> native copper.
>
>
>Isn't it just possible that you focus too strongly on perfect casting
>- the imperfections resulting from casting may not have been a real
>big deal to the ancient people.
But the imperfections due to casting pure copper *would* produce the
characteristic porosity which is *not* seen in any of the pieces other
than R666. As I have remarked in other posts, it is possible that this
single sample may have been melted due to a cause other than
deliberate casting, so by itself it is not conclusive evidence for a
copper casting technology, though it is suggestive.
In any event, none of the other objects show the porosity signature
of atmospheric casting. So even if the ancient people found flawed
castings acceptable (and such castings would be weak and brittle),
the lack of porosity is strong evidence that none of these particular
items, with the possible exception of R666, were cast.
Gary
Tom McDonald
>
> Tom McDonald wrote:
>
>>Gary Coffman wrote:
>>
>
> [..]
>
>>>As I mentioned previously, surface blisters are not what we're
>>>looking for in terms of the porosity characteristic of pure copper
>>>casting. What we need to see is a foam of microscopic bubbles,
>>>and clusters of tiny visible bubbles deep in the metal on the
>>>radiographs. That's absent from the other radiographs on the
>>>site.
>>
>> Yes, that's why I was interested in your take on R666/55786.
>>If there were other good examples of melted copper, I'd have
>>expected that the web site would have presented them.
>
>
> IT DOES!! It has been pointed to several times already. Your recent
> posting is regurgitating what you have posted before. An apparent
> casual visual inspection by the Museum curator, nothing more. Here is
> the URL again - and don't forget to scroll down a bit!!
>
> http://www.iwaynet.net/~wdc/copper.htm
>
Seppo,
As Gary has pointed out, only the item R666 (site report
artifact number), 55786 (Milwaukee Public Museum designation)
shows the characteristic porosity of melted copper; the other
copper artifacts on that page do not. My purpose in mentioning
Alex Barker's observation was merely to have an eye witness to
the artifact in question, to verify that it indeed does look
like a lump of accidentally melted or discarded copper, as
opposed to something that might have been, for instance, trimmed
off the cast after cooling. The other relevant facts about it
seem to have been adequately presented on Connor's web site.
>
>>As it is,
>>it looks as though I'll have to dig for other examples that
>>might show casting.
>
>
> Listen if the seriousness of your "looking" is equal to your looking
> on the web site - give it a miss. You wouldn't see anything anyway.
>
So far, at least as presented on this ng, the only copper
artifact that was certainly the result of melting is R666/55786.
The other artifacts Mallery (and Connor) seem to think were
cast either weren't, or don't have sufficient diagnostic
information presented to decide.
Tom McDonald
Tom McDonald
Seppo,
Thank you for the urls.
From the second link:
"Michigan’s copper deposits were remarkable for their quality
and purity. Bands of native copper were contained in outcrops 2
to 8 miles wide and of varying depth. The surface deposits first
attracted the notice of Native Americans who dug out the easily
accessible chunks and fashioned copper tools and adornments from
them."
So mining appears to have *begun* where copper deposits were on
the surface. This makes sense, as there was also drift copper
(over a wider area than just the UP mining areas), and folks
early on seem to have selectively used lumps of copper that
needed no processing. While this might not have been an every
day event, it clearly was common enough to produce many of the
copper artifacts in the region.
As to mining the copper:
"They [Indians] dug pits in the ground and separated the copper
from the stone by hammering, by the use of wedges, and,
possibly, by the use of heat. Thousands of hammers have been
found in and about the old pits."
It seems that these folks picked the visible copper out of the
debitage after beating the bejesus out of the rock. That seems
reasonable to me, as there seems to have been quite enough such
copper available to make other methods of extraction unnecessary.
The dilemma you refer to does not seem to exist. Indian people
developed the technology they needed to extract the resource
they wanted. They may have developed copper casting technology
as well. Since smelting wasn't necessary, casting would have
been a stand-alone technology. It wasn't beyond the capacity of
the Indians of the upper Great Lakes; but it also wasn't necessary.
Tom McDonald
Paul K. Dickman
Tom McDonald wrote in message <10e1l6g...@corp.supernews.com>...
>
>Paul,
>
> I'm getting a good free education in this copper business. I
>thank you and Gary for your tutelage.
>
> I don't recall reading anything about, for instance, silver
>artifacts in the upper Great Lakes area; but this doesn't mean
>it wasn't used. I rather suspect that folks were breaking rocks
>to extract copper, and may have discarded as debitage the
>non-copper bits.
>
> I'll have to look into this, as it would seem that silver might
>have been present in large enough amounts that it might have
>wound up in archaeological contexts. And, of course, when white
>folks came later to investigate and further exploit some of the
>copper deposits, I'd be surprised if any silver were to have
>been ignored by them.
>
>Tom McDonald
You're missing my point.
Given that casting pure copper is difficult and produces an inferior
product, the casting of copper, simply to save you time forging, is a fool's
errand.( Any craftsman worth his salt would figure this out by the third
try. )
The only good reasons for doing it, are to make a bigger piece of copper or
to clean the rock out.
Eventually, either of these tasks would lead to noticeable alloying.
I would expect this to show up in a full assay of the artifacts.
I've tried to follow this thread, (well, I wandered off when it turned into
a shouting match) and I've yet to see anything that says that all the
artifacts are 99+% pure copper or , in fact, that any were. I am sure that
some testing must have been done, but I am a metalsmith not an
anthropologist, and the relevant research has eluded me so, I have been
unable to ascertain this one way or the other.
Paul K. Dickman
t(nospam)kavanagh
> I don't recall reading anything about, for instance, silver
> artifacts in the upper Great Lakes area; but this doesn't mean
> it wasn't used.
Despite Inger's claim that the silver on that coconut shell was mined by
Indians, there are no pre-Columbian artifacts silver from Native North
America.
tk
Inger E Johansson
"t(nospam)kavanagh" <"tkavanag"@(nospam)indiana.edu> skrev i meddelandet
news:cbspei$bqf$1...@hood.uits.indiana.edu...
tk,
I suggest that you tell that to the Elderly of the Ojibwa's medicinemen....
You are in to a big big surprise. If it's 'Gary' you are contacting please
send him my love.
Inger E
>
> tk
Tom McDonald
Inger,
Do you mean Elders in the Midewiwin? Or do you mean some other
'medicinemen'?
If you know something about pre-Columbian silver artifacts from
North America, and especially if you know that one or more
Anishnabe (Ojibwa) Elders are aware of such, I would expect you
to provide that information. Since there are several Anishnabe
reservations in Wisconsin with which I have interacted in the
past, all you should have to do is give me a name of an Elder
who knows about this, or some key word by which it is known.
If you can't or won't do that, you are of no use to me in this
matter.
Tom McDonald
Tom McDonald
Paul,
Sorry. I got your point, but went off on my own tangent in my
reply. I have gotten the idea that casting copper of the purity
found in the UP mines and drift copper redeposited by glaciers
is, as you put it, a fool's errand when forging was well known
and widely practiced.
Your question about the purity of the copper in the artifacts
is interesting. For my part, most of my sources tend to take it
as a given that the copper artifacts in the upper Great Lakes
area were nearly pure copper. I know that I've read articles
that nail this down, and I'll try to get hold of some of them.
A kind person posted these links to articles in the Central
States Archaeological Journal. You might find them interesting
as they describe a series of experiments by one Joseph Neubauer,
Sr., designed to see how the copper artifacts observed in the UP
of Michigan could have been made. The first link is to an
article discussing the characteristics of the material he used.
The second is to a general introduction to the Neubauer
experiments, and a step-by-step discussion of his process. The
third is an overview and summary of the Neubauer Process. I'm
not a metalworker, but ISTM that most of the information needed
to replicate this Neubauer Process, and by extension the general
method known to have been used by the ancient Indians of the
area, may be found in these articles.
http://www.csasi.org/2003_summer_journal/red_metal_poundings.htm
http://www.csasi.org/2003_spring_journal/red_metal_poundings.htm
http://www.csasi.org/2004_january_journal/the_neubauer_process.htm
In the 1947 book, _Indians Before Columbus_, by Paul S. Martin,
George I. Quimby and Donald Collier, all in the Anthropology
Department of the Chicago Natural History Museum, I found this
on page 42:
"Many pieces of copper obtained from burial mounds and from
aboriginal camp sites have been chemically analyzed, with no
trace of any tempering agent ever reported. In fact, the
analyses prove conclusively that the copper in all the specimens
examined is native copper, such as is obtainable without
smelting at certain places in North America today, and that the
aboriginal inhabitants were ignorant of the process of
recovering copper from copper ores or of tempering or hardening
by alloying copper with other metals."
I'll keep looking, however I have yet to come across any good
evidence that the copper artifacts in the upper Great Lakes
region were made from anything but the ca. 99.75+% pure copper,
with occasional incidental inclusions of very small amounts of
other materials.
Hope that is helpful.
Tom McDonald
t(nospam)kavanagh
I suggest you tell us which Ojibwa elder medicine men told you that that
they had smelted silver pre-columbian era, and provide evidence.
Who is Gary?
tk
t(nospam)kavanagh
ps. I have cast silver in tuffa (my belt buckle and the bracelet that I
wear today) as well as the lead bullets which I cast to shot in the
N-SSA (see: http://www.n-ssa.org/)
> tk
Gary Coffman
The important point of Paul's excellent post is that if you find
silver *inclusions* in the artifacts, you know that the copper
was never melted (because the melting point of silver is below
that of copper, and the inclusion wouldn't exist if the copper
had been heated to melting).
The Neubauer articles you posted show these silver inclusions in
both ancient and newly made copper tools wrought from Michigan
native copper (also shown are the blisters produced by annealing
and pounding which Conner incorrectly claims are evidence of
casting).
OTOH, Paul is also telling us that if chemical analysis were to show
an actual silver-copper alloy of uniform composition throughout an
artifact, you could then reasonably conclude that it had been molten
at some point.
I should note that the 15% silver assay Paul mentioned is not
the same thing as saying you have a 15% alloy. Assay doesn't
differentiate between inclusions and alloys. So don't be led
astray by that.
If the object is high purity copper (less than 0.5% alloy), doesn't
show characteristic porosity, and/or has silver inclusions, then
you can be very certain it was never melted and never cast.
That appears to be descriptive of all but one of the artifacts
brought into evidence.
OTOH, if chemical analysis of the object were to show it is a
true alloy of copper and other metals (mainly silver for Michigan
native copper), and there is characteristic porosity (because
silver is not an effective deoxidant for copper), then you can
be confident that it has been melted in atmosphere.
Now that's *suggestive* that it may also have been cast, but as
Paul notes, it may merely have been consolidated into an ingot
which was then wrought into the artifact you're examining. And
as I've noted, the melting of the particular artifact which does
show characteristic porosity could have been accidental.
The Neubauer articles provide testimony of large amounts of
small pieces of copper debris, like that produced when smithing
copper in the Neubauer manner, found at native work sites which
would only be there if they were *not* systematically melting and
consolidating small pieces of copper. So even ingot production
seems unlikely.
The more I look at this, the more the evidence piles up that
the Michigan works did not involve casting of copper. Rather,
the evidence, taken together, strongly indicates the Native
Americans wrought native copper in ways likely to be similar
to those used by Neubauer rather than casting them as some
would like to claim.
The reasons I can draw that conclusion are that the artifacts
appear to be mostly pure copper with little or no evidence of
alloying, there are silver inclusions in some of the artifacts
which is proof positive that they haven't been melted, some
have blisters indicative of zealous annealing and pounding
rather than melting, and there has only been one artifact
shown to have the characteristic porosity caused by
atmospheric melting, and that one may have been the result
of an accidental exposure at some point to temperatures in
excess of 1877F (a forest fire is a scenario I suggested to
produce that high temperature).
One further point. *If* casting technology were being used,
we'd expect to find numbers of identical artifacts, since that's
what casting in molds produces. But in fact we don't find numbers
of identical artifacts. We find artifacts of the same *style*, but
differing in dimensions.
Neubauer says, correctly, that's a result of the necessity of
following the copper when working it. In other words, the size
and composition of any particular chunk of native copper
dictates how much you can move and shape the metal, so it
decides what sort and size of tool you can make from it.
I'd also like to reiterate something else Paul implied. The
apparent fact that the Native Americans *didn't* cast native
copper is an indication that they were intelligent and economical
craftsmen. If they had tried casting, they would have quickly
discovered it was an inferior method of utilizing the abundant
raw materials available to them to produce a final product.
They weren't forced to deal with poor ores, they had abundant
chunks of native copper of the appropriate sizes to smith
anything they wished, and had no need to salvage small scraps.
They could simply "high grade" the sites. So the intelligent thing
to do would have been to work the way they apparently did,
smithing instead of founding.
Gary
Gary Coffman
>Tom McDonald wrote:
>> In the context of this thread, at least its original context,
>> the copper was native copper in the upper Great Lakes area of
>> the US and Canada. That copper is typically well over 99% pure
>> out of the ground, and does not have to be smelted to remove
>> impurities. If another context is in evidence, then a
>> definition of the term 'pure' is needed.
>
>http://www.dayooper.com/Networks.JPG
>
>The copper may well be 99% pure - what about the rest? It isn't every
>day people find huge lumps of pure copper without impurities embedded
>within it. This is the dilemma that people bypass and ignore.
>
>This has a good story about the Great lakes Copper deposits.
>http://www.geo.msu.edu/geo333/copper.html
As that article notes, 14 billion pounds of copper have been removed
from the area since the ancients were working copper there. Let the
enormity of that number sink in. There was an *awful lot* of copper
there in ancient times, much of it easily accessible from the surface.
Note also, as Neubauer does, that they didn't want "huge lumps".
Copper is difficult to cut with primitive tools (isn't all that much fun
with modern steel chisels). Neubauer suggests that the ancients
would want to start with a piece of about the right size for the
object they wanted to make. At most that would be a lump weighing
a few pounds, in the vast majority of cases it would be a lump smaller
than a hen's egg. Even today, such lumps are relatively plentiful in
the copper belt. They were vastly more so 6,000 years ago before
modern industrial man started extracting copper from the region.
Gary
Martyn Harrison
<ke...@bellsouth.net> said:
>shown to have the characteristic porosity caused by
>atmospheric melting, and that one may have been the result
>of an accidental exposure at some point to temperatures in
>excess of 1877F (a forest fire is a scenario I suggested to
>produce that high temperature).
We did come up with the idea that you might get this sort of temperature in a
funeral pyre, because you need that sort of temperature to turn the body to
ash.
Tom McDonald
I now think that it's unlikely that the melted bit was from a
cremation, although it's not impossible. It wasn't found in a
burial context, for one thing.
For another, at least one study of cremations at the Riverside
site appear to indicate that the typical cremation fire was
either not hot enough, or not maintained long enough, to fully
reduce all of the bones. Since cremation temperatures are
typically well below the melting point of copper (by over 300
degrees F, in several references), that scenario seems less
likely that I first thought. I'd go with Gary on this one,
especially as the occupation was aceramic.
If you are interested in following up on this, there is an
article entitled, 'Analysis of a Cremated Burial from the
Riverside Cemetery, Menominee County, Michigan', pp. 383-389,
_An Archaeological Perspective_, 1972, Lewis Binford. Seminar
Press, London. The article prior to that one is a comparative
study of three other Michigan Late Archaic (Red Ocher)
cemeteries, comparing a total of eight burials.
Note: some burials, as with the Riverside burial in the noted
article, include more than one individual. The Riverside burial
included a MNI of 4, three adults and a child.
Tom McDonald
Yuri Kuchinsky
[snip]
> The apparent fact that the Native Americans *didn't* cast native
> copper
This is a "fact" only if you disregard all evidence to the
contrary, as you appear to be doing.
Yuri.
Yuri Kuchinsky -=O=- http://www.trends.ca/~yuku
A great many people think they are thinking when they are
merely rearranging their prejudices -=O=- William James
Yuri Kuchinsky
> >Isn't it just possible that you focus too strongly on perfect casting
> >- the imperfections resulting from casting may not have been a real
> >big deal to the ancient people.
>
> But the imperfections due to casting pure copper *would* produce the
> characteristic porosity which is *not* seen in any of the pieces other
> than R666. As I have remarked in other posts, it is possible that this
> single sample may have been melted due to a cause other than
> deliberate casting,
Not everything that is possible is probable.
Wishing won't make it so.
Yuri Kuchinsky
>
> Yuri Kuchinsky wrote:
>
> > Gary Coffman wrote:
> >
> >>On Mon, 28 Jun 2004 09:04:49 +1200, Eric Stevens <eric.s...@sum.co.nz> wrote:
> >>
> >>>On Sun, 27 Jun 2004 03:03:50 -0400, Gary Coffman <ke...@bellsouth.net>
> >>>wrote:
> >>>
> >>>>On Wed, 23 Jun 2004 23:46:01 -0500, Tom McDonald <tmcdon...@charter.net> wrote:
> >>>>
> >>>>>Eric Stevens wrote:
> >>>>>
> >>>>>>On Fri, 11 Jun 2004 22:57:04 GMT, ke...@bellsouth.net (Gary Coffman)
> >>>>>>wrote:
> >>>>>>
> >>>>>>>But that said, casting pure copper is a bitch.
> >>>>>>
> >>>>>>
> >>>>>>This from the guy who has just written that the task can be undertaken
> >>>>>>by low-skilled workers?
> >>>>>
> >>>>> Eric, I read that to mean that casting, in general (as with
> >>>>>iron, silver, bronze, gold, etc.) can be done by folks with
> >>>>>fewer skills than smiths. However, copper appears to present
> >>>>>particular problems with casting that are not so pronounced with
> >>>>> other metals, and which require higher skill levels than would
> >>>>>be required by those who cast other metals.
> >>>>
> >>>>Exactly, and further, skill alone isn't sufficient to make sound
> >>>>castings of pure copper. The proper equipment is also required.
> >>>>Specifically, an inert atmosphere furnace. That technology
> >>>>didn't exist until the late 19th century.
> >>>
> >>>Just as well the ancient egyptians didn't know that they couldn't do
> >>>what they were doing. :-)
> >>
> >>So, are you claiming to have evidence that the ancient Egyptians
> >>successfully cast pure native copper?
> >>
> >>extremely rare in Egypt. Almost all of the copper they had was
> >>refined from ores (smelted), and the results were *not* pure
> >>copper. Rather, they were alloys, whether intentional or not,
> >>of copper, arsenic, zinc, iron, or tin. These alloys behave *very*
> >>differently from pure native copper when casting is attempted.
> >>
> >
> >
> > Well, Gary, the folowing sure seems to imply that the
> > ancient Egyptian did some copper casting.
> >
> > [quote]
> >
> > Ancient Egyptian raw materials: metals - copper, bronze,
> > iron, gold, silver, lead
> > http://nefertiti.iwebland.com/trades/metals.htm
> >
> >
> > Re: copper objects [rather than bronze]:
> >
> > The objects were generally cast, which is quite difficult to
> > do with copper because of the formation of gas bubbles
> > during the pouring of the metal and its shrinking when it
> > cooled down. Then they were hammered cold to give them their
> > final form.
> >
> > [unquote]
>
> Yuri,
>
> Your site tells us that copper ore was what was available, not
> native copper; and that it had to be smelted before use. IOW,
> it's not clear whether the Egyptians ever had copper of the
> purity of the native copper in the upper Great Lakes area. In
> addition, the smelting and melting of that copper would more
> than likely have resulted in a copper alloy, not pure copper.
>
> Of course, if you have better evidence that shows Egyptians
> cast 99+% pure copper, you are welcome to present it here. I
> for one would be very interested in that evidence.
>
> Tom McDonald
My main point here is that Gary Coffman is wrong with his
speculations that copper casting was too difficult for
ancient peoples to do.
I'm merely trying to teach Mr. Coffman a few things about
metalworking, as it applies to ancient peoples.
Gary Coffman
Perhaps. I know nothing about the funeral practices of the
Native Americans of Michigan. Modern crematory practice
uses a temperature between 1400F and 1800F in a gas
fueled oven. The upper end of that range is just below the
melting point of copper. An ideally laid large wood fueled
pyre might produce enough draft to reach a higher temperature.
Gary
Tom McDonald
> Gary Coffman wrote:
>
> [snip]
>
>
>>The apparent fact that the Native Americans *didn't* cast native
>>copper
>
>
> This is a "fact" only if you disregard all evidence to the
> contrary, as you appear to be doing.
Yuri,
Please elaborate.
Tom McDonald
Tom McDonald
> Gary Coffman wrote:
>
>>On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors <Ren...@not.com.au>
>>wrote:
>
>
>>>Isn't it just possible that you focus too strongly on perfect casting
>>>- the imperfections resulting from casting may not have been a real
>>>big deal to the ancient people.
>>
>>But the imperfections due to casting pure copper *would* produce the
>>characteristic porosity which is *not* seen in any of the pieces other
>>than R666. As I have remarked in other posts, it is possible that this
>>single sample may have been melted due to a cause other than
>>deliberate casting,
>
>
> Not everything that is possible is probable.
>
> Wishing won't make it so.
Yuri,
Exactly. So why are you clinging to your wishful thinking,
instead of researching the issue?
Tom McDonald
Tom McDonald
Yuri,
I've been boggled by things you've written before, but this
takes the cake. *You* teaching *Gary* anything about
metalworking by the ancients. Priceless!
Gary hasn't written that casting was too difficult for ancient
peoples to do. Clearly, they did. But in the case of copper in
the upper Great Lakes area, copper casting was totally
unnecessary. Also, with any even remotely likely technology
available to the Indians here, the resulting pure copper casts
would be very inferior to the same artifacts made by smithing.
You are trying to tell us that Indians in the Great Lakes
Archaic period cast pure copper with techniques that not only
perfectly mimicked smith work, but also of such quality that
even today it is hard to do so well. You also want us to
believe that this technology left no trace other than the
artifacts. You finally want to tell us that the Indians,
obviously very savvy folks, developed this technology that looks
precisely like smithing for no reason whatsoever.
As Gary and Paul have pointed out, the intelligent thing for
folks to do with the kind and quality of copper available to
them would be to hammer it, using cold hammering and annealing.
If you have evidence of archaeological sites in the upper Great
Lakes that show evidence of the technology required (re-read
Gary and Paul's posts, and follow the links to the Neubauer
Process for what to look for), present it.
Teaching Gary about metalwork :-). Priceless, just priceless.
Tom McDonald
Eric Stevens
<nos...@spammers.of.the.world.unite> wrote:
You might GET that temperature but you don't NEED that temperature.
See
http://www.funeralplan.com/funeralplan/cremation/cremationprocessing.html
"1,400 and 1,800 degrees fahrenheit" - approx 760C - 982C which is
less than the 1083C needed to melt copper. Even the formation of deep
copper oxides requires about 1060C.
Eric Stevens
Gary Coffman
>Gary Coffman wrote:
>
>[snip]
>
>> The apparent fact that the Native Americans *didn't* cast native
>> copper
>
>This is a "fact" only if you disregard all evidence to the
>contrary, as you appear to be doing.
Virtually all of the evidence presented to date in this thread is
against casting of ancient Michigan native copper artifacts. If
you have conclusive evidence showing characteristic porosity
in all the items claimed to be cast, if you have evidence showing
a chemical analysis of true alloying between the native copper
and other metals (mainly silver) found with it in the halfbreed
ore matrix, if you have evidence of large numbers of identically
dimensioned artifacts representative of a casting provenance,
etc, then present it. Otherwise you have no case.
What we do know is that ancient Michigan artifacts have been
found with silver inclusions. That precludes the possibility that
they were ever melted. We do know that of the artifacts which
have been put forward as evidence of copper casting, all but
one do *not* show the characteristic porosity of atmospheric
melting of copper, and that one does not appear to be a deliberate
casting.
We do know that there is no need to invoke casting as the
manufacturing method of any of the artifacts, ie it has been
demonstrated that any of them could have been smithed
from native copper without casting using tools and techniques
known to have been available to the Native Americans of
Northern Michigan. And we have the testimony of an experienced
coppersmith that casting would have been a greatly inferior
method of producing them.
The burden of proof is on you to present incontrovertible
evidence that any of the Michigan artifacts were in fact cast.
So far, you have not done so.
Gary
Paul K. Dickman
Eric Stevens wrote in message
<3ub6e0t3rgo3hg22p...@4ax.com>...
Even they don't completely reduce the body to ash. The teeth and several
large pieces of bone are left behind, they get run through a ball mill
before they return the ashes.
Paul K. Dickman
Eric Stevens
wrote:
>On Wed, 30 Jun 2004 14:53:00 -0400, Yuri Kuchinsky <yu...@trends.ca> wrote:
>>Gary Coffman wrote:
>>
>>[snip]
>>
>>> The apparent fact that the Native Americans *didn't* cast native
>>> copper
>>
>>This is a "fact" only if you disregard all evidence to the
>>contrary, as you appear to be doing.
>
>Virtually all of the evidence presented to date in this thread is
>against casting of ancient Michigan native copper artifacts.
I presume that you regard evidence 'against' as different from lack of
evidence 'for'.
What is the evidence 'against' to which you are referring?
What about radiographs cited by Mallery? These have been mentioned
several times.
Eric Stevens
Tom McDonald
<snip>
>
> What about radiographs cited by Mallery? These have been mentioned
> several times.
Eric,
Gary has discussed this several times. In essence, the
radiographs on Connor's web site cited by Mallery were
apparently not cast. What Mallery considered bubbles
characteristic of cast copper appear to be, with one exception,
*not* the type of bubbles one finds in casts of copper of the
purity seen in the artifacts.
The sole exception, the artifact labeled R666 (Riverside site
artifact number), or 55786 (Milwaukee Public Museum catalog
number--where the artifact is curated), does show the typical
porosity. However, I don't think anyone thinks that the
artifact is an example of intentional casting, but rather of
accidental or natural (e.g.: forest fire) melting of a bit of
copper.
OTOH, some of the radiographs clearly show annealing twins, and
linear voids characteristic of smithing.
This has been discussed before in this thread, perhaps before
you returned. If any of this seems new to you, you might want
to read the thread in Google groups.
Tom McDonald
Inger E Johansson
it seems as if you and Gary aren't aware of anything but what's on Connor's
website in this question.
I know for a fact that Eric has had some of the information Mallery gained
by letting Keeler help him to the best metallurgic specialist there was,
actually still much more credited than most today.
I know also for a fact that Mallery's analysereports aren't in Connor's
website, no matter that it contain a lot of other interesting details.
As some reading this already knows Mallery's papers are preserved in
Keeler's deposit in a private Museum. Lot's of documentation as well as some
of the most discussed findings of Mallery and testresults showing beyond any
reasonable doubts that we are discussing casting and nothing else what so
ever.
I rest there for the moment. Eric hasn't had all information but some
essential parts of it.(not sent by me) I will go thru my discs looking for
an indexlist I know I have re. the deposit.
More later.
Inger E
"Tom McDonald" <tmcdon...@charter.net> skrev i meddelandet
news:10e7c3d...@corp.supernews.com...
Seppo Renfors
Gary Coffman wrote:
>
> On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors <Ren...@not.com.au> wrote:
> >Gary Coffman wrote:
[..]
> >> Again, porosity is the problem, and that should show up on
> >> radiographs, as it does for R666 (which certainly shows evidence
> >> of being melted in atmosphere, though not necessarily evidence
> >> of being cast), but none of the other artifacts presented show
> >> that sort of porosity.
> >
> >See:
> >http://www.iwaynet.net/~wdc/copper.htm
> >
> >The 4th and 5th pictures down.
>
> Those pictures do not show any evidence of the characteristic
> porosity copper casting would produce.
They disagree with you as it states "The casting bubble can clearly
been seen...."
> The single large surface
> bubble is a blister, common when the surface of a wrought piece
> is overheated. Compare it to the radiograph of R666. The latter
> does show the characteristic deep pattern of porosity of an at least
> partially melted copper object.
In my experience of examples of all kinds - no two are ever identical.
>
> >> I believe we are agreed that only atmospheric casting was within
> >> reach of the ancient Native Americans (or ancient Old World
> >> founders for that matter), so we *should* see characteristic
> >> porosity in any pure copper items they attempted to cast. Now
> >> of course the Old Worlders had the advantage of ores which
> >> did contain suitable deoxidizers. They weren't actually casting
> >> pure copper. But the Michigan copper was essentially pure
> >> native copper.
> >
> >
> >Isn't it just possible that you focus too strongly on perfect casting
> >- the imperfections resulting from casting may not have been a real
> >big deal to the ancient people.
>
> But the imperfections due to casting pure copper *would* produce the
> characteristic porosity which is *not* seen in any of the pieces other
> than R666.
Again, I point to the fact they disagree.
> As I have remarked in other posts, it is possible that this
> single sample may have been melted due to a cause other than
> deliberate casting, so by itself it is not conclusive evidence for a
> copper casting technology, though it is suggestive.
One cant make that claim without investigation, there hasn't been any
undertaking by others do examine artefacts for casting. Again I point
to the article:
Neiburger said "Further xeroradiographic surveys and analysis of the
25,000 existing copper artifacts from that period (Archic Midwestern
United States) are necessary for the determination of how extensively
early Native Americans had used melted metal."
It doesn't look like any real studies has been done to say casting was
NOT practised - or that it was. Personally I don't expect a hell of a
lot of casting due to the pure copper being available (even if not
always in large lumps) - but I cannot dismiss the evidence, limited as
it is, considering the LACK of research undertaken so far.
> In any event, none of the other objects show the porosity signature
> of atmospheric casting. So even if the ancient people found flawed
> castings acceptable (and such castings would be weak and brittle),
> the lack of porosity is strong evidence that none of these particular
> items, with the possible exception of R666, were cast.
>
> Gary
--
SIR - Philosopher unauthorised
-----------------------------------------------------------------
The one who is educated from the wrong books is not educated, he is
misled.
-----------------------------------------------------------------
Seppo Renfors
Tom McDonald wrote:
>
> Seppo Renfors wrote:
> >
> > Tom McDonald wrote:
> >
> >>Gary Coffman wrote:
> >>
> >
> > [..]
> >
> >>>As I mentioned previously, surface blisters are not what we're
> >>>looking for in terms of the porosity characteristic of pure copper
> >>>casting. What we need to see is a foam of microscopic bubbles,
> >>>and clusters of tiny visible bubbles deep in the metal on the
> >>>radiographs. That's absent from the other radiographs on the
> >>>site.
> >>
> >> Yes, that's why I was interested in your take on R666/55786.
> >>If there were other good examples of melted copper, I'd have
> >>expected that the web site would have presented them.
> >
> >
> > IT DOES!! It has been pointed to several times already. Your recent
> > posting is regurgitating what you have posted before. An apparent
> > casual visual inspection by the Museum curator, nothing more. Here is
> > the URL again - and don't forget to scroll down a bit!!
> >
> > http://www.iwaynet.net/~wdc/copper.htm
> >
>
> Seppo,
>
> As Gary has pointed out, only the item R666 (site report
> artifact number), 55786 (Milwaukee Public Museum designation)
> shows the characteristic porosity of melted copper; the other
> copper artifacts on that page do not.
Are you ignoring completely what is written on that site? I refer you
to my reply to Gary for more details.
> My purpose in mentioning
> Alex Barker's observation was merely to have an eye witness to
> the artifact in question, to verify that it indeed does look
> like a lump of accidentally melted or discarded copper, as
> opposed to something that might have been, for instance, trimmed
> off the cast after cooling. The other relevant facts about it
> seem to have been adequately presented on Connor's web site.
I see..... so now you are actually editorialising about the
information given to you. You claim "accidentally melted" contrary to
what has been said. First of all "accidental" heating in a fire is not
possible as it doesn't get hot enough. So it requires a forced draught
for it to melt, and how the hell do you generate something
specifically built for melting as "accidental"?
>
> >
> >>As it is,
> >>it looks as though I'll have to dig for other examples that
> >>might show casting.
> >
> >
> > Listen if the seriousness of your "looking" is equal to your looking
> > on the web site - give it a miss. You wouldn't see anything anyway.
> >
>
> So far, at least as presented on this ng, the only copper
> artifact that was certainly the result of melting is R666/55786.
But only if you ignore claims made on that web site. There is a
considerable amount of common sense totally discarded as well - see
message by Dickman:
<cbqhn...@news3.newsguy.com>
It is actually unlikely any melted copper is actually "pure", but in
reality is an alloy - most probably of silver. I have pointed out
these problems previously. They are ignored, and a make believe of a
cliff of pure copper exists that people come and hack a piece as big
as they want from it. See also:
This deals with what I said above. Again this point has been ignored
including by yourself - I have noted your replies still harping on
pure copper.
> The other artifacts Mallery (and Connor) seem to think were
> cast either weren't, or don't have sufficient diagnostic
> information presented to decide.
Your "don't have sufficient diagnostic" does NOT eliminate one single
artefact from potentially being cast. Yet what I see is claims made by
researchers being discarded in favour of ignorance, and by the use of
ignorance, as that IS what rejecting something as cast on the basis of
"don't have sufficient diagnostic" amounts to.
Tom McDonald
You're funny, Seppo. Don't ever change.
Tom McDonald
Seppo Renfors
Gary Coffman wrote:
>
> On Tue, 29 Jun 2004 07:05:25 GMT, Seppo Renfors <Ren...@not.com.au> wrote:
> >Tom McDonald wrote:
> >> In the context of this thread, at least its original context,
> >> the copper was native copper in the upper Great Lakes area of
> >> the US and Canada. That copper is typically well over 99% pure
> >> out of the ground, and does not have to be smelted to remove
> >> impurities. If another context is in evidence, then a
> >> definition of the term 'pure' is needed.
> >
> >http://www.dayooper.com/Networks.JPG
> >
> >The copper may well be 99% pure - what about the rest? It isn't every
> >day people find huge lumps of pure copper without impurities embedded
> >within it. This is the dilemma that people bypass and ignore.
> >
> >This has a good story about the Great lakes Copper deposits.
> >http://www.geo.msu.edu/geo333/copper.html
>
> As that article notes, 14 billion pounds of copper have been removed
> from the area since the ancients were working copper there. Let the
> enormity of that number sink in. There was an *awful lot* of copper
> there in ancient times, much of it easily accessible from the surface.
My main interest was to show the formation of the copper deposits -
the volcanic activity that melted it (and other minerals with it).
Silver is/was found in fair quantities alongside the copper. What
isn't known - because nobody cares to find out, is the composition of
the metal used in the artefacts. It is ASSUMED to be pure copper.
The knowledge of the size of excavations by the ancients suggests vast
quantities had already been mined. Only a very small fraction of it
has ever been found. The question has been posed, what happened to the
rest of it?
> Note also, as Neubauer does, that they didn't want "huge lumps".
> Copper is difficult to cut with primitive tools (isn't all that much fun
> with modern steel chisels).
One thing we always do is under estimate the ancient people's
abilities. How the hell they ever managed to get vast stone slabs dead
level and polished to a mirror finish, is hard to comprehend, but they
did. The huge stone blocks for the pyramids, cut with copper saws. The
fine detail on gold necklaces we would need magnification to see and a
brain surgeon's steady hand and modern tools to achieve.....
> Neubauer suggests that the ancients
> would want to start with a piece of about the right size for the
> object they wanted to make. At most that would be a lump weighing
> a few pounds, in the vast majority of cases it would be a lump smaller
> than a hen's egg. Even today, such lumps are relatively plentiful in
> the copper belt. They were vastly more so 6,000 years ago before
> modern industrial man started extracting copper from the region.
Knowing that mining was done by the ancient, including under ground
mining, then if the above was the case - where are all the piles of
copper not found to be suitable?
I don't deny lumps existed - merely that they were rare in comparison
to other copper in many forms, oxidised or thin as paper in cracks or
embedded in other rock as per the first URL. An axe head requires to
be a bit bigger than a chook egg size - more like an Emu egg size!
At village sites there should exist copper scraps in considerable
quantities if such was simply discarded as "useless" if not big enough
for the task at hand. Nobody has pointed to such as yet at least.
Seppo Renfors
Gary Coffman wrote:
>
> On Wed, 30 Jun 2004 14:53:00 -0400, Yuri Kuchinsky <yu...@trends.ca> wrote:
> >Gary Coffman wrote:
> >
> >[snip]
> >
> >> The apparent fact that the Native Americans *didn't* cast native
> >> copper
> >
> >This is a "fact" only if you disregard all evidence to the
> >contrary, as you appear to be doing.
>
> Virtually all of the evidence presented to date in this thread is
> against casting of ancient Michigan native copper artifacts. If
> you have conclusive evidence showing characteristic porosity
> in all the items claimed to be cast, if you have evidence showing
> a chemical analysis of true alloying between the native copper
> and other metals (mainly silver) found with it in the halfbreed
> ore matrix, if you have evidence of large numbers of identically
> dimensioned artifacts representative of a casting provenance,
> etc, then present it. Otherwise you have no case.
You cannot claim "you have no case" UNLESS you prove there is no "true
alloying between the native copper and other metals" and that takes an
analysis of the metals in the artefacts found. It works both ways you
know.
> What we do know is that ancient Michigan artifacts have been
> found with silver inclusions. That precludes the possibility that
> they were ever melted.
No, it precludes that item from having been melted only. You cannot
extrapolate that beyond the artefact itself.
> We do know that of the artifacts which
> have been put forward as evidence of copper casting, all but
> one do *not* show the characteristic porosity of atmospheric
> melting of copper, and that one does not appear to be a deliberate
> casting.
We see TWO artefacts being claimed as being cast - one being conceded
as being cast. We don't know the composition of the metal of the
second artefact to be able to discard it as "not cast".
You have claimed it is the sign of "copper" being overheated - ie to
melting point else bubbles cannot form. At the same time you have also
stated the heat source has to be forced air type to get it hot enough
to melt copper.
I see those two statements as being inconsistent with each other. If
the Copper was simply hammered and annealed, the temp should NOT be
able to get high enough to cause any bubbling.
ON the other hand in the event the fire was of the type for melting
copper.... well.... then it would be for melting copper, why else
would it be like it?
> We do know that there is no need to invoke casting as the
> manufacturing method of any of the artifacts, ie it has been
> demonstrated that any of them could have been smithed
> from native copper without casting using tools and techniques
> known to have been available to the Native Americans of
> Northern Michigan. And we have the testimony of an experienced
> coppersmith that casting would have been a greatly inferior
> method of producing them.
>
> The burden of proof is on you to present incontrovertible
> evidence that any of the Michigan artifacts were in fact cast.
> So far, you have not done so.
No, I don't see it like it at all. The alternative is to argue that;
without any research we can definitely say none were cast, barring one
exception. That of course is illogical as all hell. NO such thing can
be claimed at all.