In alt.language.latin message <
abtfsk...@mid.individual.net>, Wed,
19 Sep 2012 10:00:24, Johannes Patruus <inv...@invalid.invalid> posted:
Undoubtedly. I copied the Latin with care, combining a fully legible
partial copy and a hard-to-read complete original; I used Google to
locate untranslatable and therefore probably erroneous words to be
emended; and I then checked carefully against the sources. But there
will be some errors left (I ought to have recognised that one, though).
>Note 2 - The Latin "duplicata", at least in the classical lexicon,
>conveys the notion of doubling rather than of squaring, for which one
>might have expected "quadrata".
Obviously the meaning is "squared"; I think the construction means
"proportional to (the inverse of the distance), twice" - and, earlier,
not exactly "proportional to (the product of the masses)", but
"proportional to one of the masses and also to the other of the masses".
In places, the "ordinary English" that best matches the Latin will need
re-translation into the English used by modern mathematicians,
physicists, astronomers, who are the intended readership. On that
basis, since attractions pull rather than push, I'll render "urgetur" as
"urged" rather than the linguistically-accurate "pushed".
So, copied from the fair copy now on the Web at
<
http://www.merlyn.demon.co.uk/euler304.htm#Enestrom304>,
page 544 column 4,
"The true cause of all celestial motions lies, of course, in the
mutual attraction of these bodies by which they are urged
towards each other by forces holding a compound reckoning from
the product of the masses and the inverse square of the
distances."
That is intended to take account of subsequent articles up to about Sept
19th, 22:45 GMT, when I last collected News; and Google Groups shows no
others.
The next sentence is
"Semper autem commode usu venit, ut inter has vires una prae reliquis
maxime emineat, ideoque motus proxime regulis Keplerianis conformis,
evadat ; sicque effectus a reliquis oriundus veluti minimus per methodos
appropinquandi definiri possit."
My initial aim was to determine whether, in this document (the next one,
thankfully, is in French, and is better printed), Euler predicted any of
the Lagrange Points. Ideally, I'd have done it by reading an English
version via the Euler Archive at
<
http://eulerarchive.maa.org/pages/E304.html> - but none is available.
(<
http://eulerarchive.maa.org/pages/E327.html> does link to my version
of a later paper, and it will be nice if I can provide an adequate
version of E.304).
There is no suggestion of Euler discovering L4 & L5, the equilateral
configuration; and, if he had, I'm confident that I would have
recognised the inescapable words for equilateral or equiangular - if
looking in the right E-number.
For L1 L2 L3, the Pseudo-Moon is permanently in a straight line with Sun
and Earth and at a fixed position on that rotating line :
^
|
L1: Sun Earth PM
L2: Sun PM Earth
L3: PM Sun Earth
|
V
I think that, in Section 7, Euler refers to L1.
In section 8, Euler talks of an equation of the fifth degree, and I
assert that such an equation is used to locate L1 L2 L3.
Late in Page 550, "seu si Luna fere quater longius a nobis esset
remota,", a minor question : does he mean multiplying the Moon's
distance from Earth by 4, or adding an extra 4 times, making 5 times the
distance? 4 is a reasonable fit to the true value (5.5), but 5 would be
better.
But is there anything about L3, the "Counter-Earth" point? Probably not
after Section 10, since there the maths is too complicated for that.
Thanks for the continued help. I'm continuing to attack the easier-
looking parts of the later sections, among the maths.
--
(c) John Stockton, nr London, UK. For Mail, see Home Page. Turnpike, WinXP.
Web <
http://www.merlyn.demon.co.uk/> - FAQ-type topics, acronyms, and links.
Command-prompt MiniTrue is useful for viewing/searching/altering files. Free,
DOS/Win/UNIX now 2.0.6; see <URL:
http://www.merlyn.demon.co.uk/pc-links.htm>.