Bronton Compass
Richard Pearce
I am interested in astronomy and I recently found at a local market a
scientific instrument which intrigued me. It is a compass labelled, by the
seller, as a Bronton Compass. I have searched the internet and have
discovered that this is the case. I cannot find any date on the instrument
but it does have the manufacturers name of "Stanley London". It is made of
brass and weighs about 17ounces and includes a natural sine table on the
lid.
I would be grateful if somebody could tell me how to use this compass and
what it was originally designed for. I suspect it is some kind of marine
compass but I cannot see how it was used.
If it helps scanned images of the subject compass can be found at;
http://www.users.zetnet.co.uk/astro_pics/compass.html
Many thanks.
--
Richard Pearce
Real email rpearce at zetnet.co.uk
Gerald Clough
The correct name of this design is the Brunton Pocket Transit, designed
by Colorado mining engineer D. W. Brunton and patented in 1894. It is
one of the most reproduced and fraudulantly marketed fakes in the
business, as well as being openly sold as reproductions. The originals
were finished very differently than the repros, which are all plain
brass, as yours is. The "Stanley London" was the stamp of Stanley & Co.
which made the originals. Reproducers other than Stanley London also
stamp theirs the same way. Other fake antique instruments are stamped
with other old maker marks. Most also have poor quality printing on the
roses that is obvious under a glass.
The fakes are peddled in quantity to antique dealers who don't mind
presenting fakes to folks. They usually have one of each item out to
display and a box full of others to draw on when one sells. When
pressed, the dealer will back away from any specific claim to age or
origin. Of course, they really *are* Bruntons, in the sense that it's
Brunton's design. Some try to maintain a sort of innocence through a
nudge-nudge-wink-wink relationship with their supplier where no one
actually says they're antiques, but they both know exactly what they're
doing. The more outrageous or terminally naive tell stories of a
recently discovered warehouse of old British military stores in India.
One of the tip-offs for those that turn up locally is that if you use a
strong glass to examine the lettering and numbering, you will see that
they are tapped out in tiny dots, rather than being stamped.
Presumably, the Indian makers who crank them out can't afford the
stamps. If it really is labeled "BRONTON", that's not unusual, as the
fakes are often labeled with variations on the spelling. The fakes are
readily available for $25 to $30 from Stanley London
http://www.stanleylondon.com/ or any number of other places that sell
reproduction brass military, surveying, and nautical instruments, nearly
all of modern Indian manufacture.
There obviously *are* original Bruntons around, but few or none of them
were unfinished brass, but they are enormously outnumbered by the fake
"antiques". Beware of all nice, heavy brass instruments in remarkably
good condition.
For some photos and descriptions of originals and fakes:
http://www.gemmary.com/rcb/ffiles/
--
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Clo...@Texas.Net
"Nothing has any value unless you know you can give it up."
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Tony
This is a surveyors compass. It is used by holding the compass part
horizontally and standing the mirror part and the alignment piece (opposite)
vertically. Then sight toward a distant object through the two alignment
marks (one is a wire I think) and at the same time read the angle via the
mirror.
Such devices are no longer in use, having been outdated by the
circumferenter and later the transit theodolite. Perhaps still usefull for
reconnaissance though.
The table of natural sines is there for the calculation of coordinates
from the observed angle and a distance which would be determined, usually by
chain.
Regards,
Tony Mexon
B. Surveying
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