ORRERY. 
The pinions on the earth’s arm may be any two of equal 
pape both above and helow ; likewife on Jupiter’s arm, 
d at the earth’s axis : and onal the diameters are taken, 
it is underftood to be acrofs from the pitch line to the pitch 
line, without the ends of the teeth, which will be inverfely in 
er Freach work has juft come 
our Mende s, entitled « Des Réealutions des Corps Cé- 
leltes par le Méchanifm des Rouages,’’ 1812, Paris, = an 
eminent mechanic, whofe contrivances have been honoured 
by an examination and report upon them, made by the clafs 
of phyfical and ae eer bata at the Imperial In- 
e of France. The a is a 
- 3 
. 
his policy, in the obfcurity of our retreat, without a n 
and without a title, we prefame to form an witerprine al almo 
d the reac me when our intel- 
vourable regar reat Napoleon, the coup-d’ceil of 
Maria Louifa, ‘he defire of becoming ufeful to the inftruc- 
tion of an auguit prince called to — to fo much glory, 
and to bear fo many diadems ; hae e can be wanting to 
ar Hope and to furnifh us 
ty fo or the aaa of a“ art, in which we have al- 
obtained confiderable fuc — Such is the exordium 
_ ae defcription of this She from the perufal of which 
we had hoped to gain much ufeful information for the fervice 
of our readers, as well as amufement for | 3 but, to 
our difappointment, the author has not red the world 
ith an account of the numbers conte the teeth of 
nd gives as a reafon fo omiffion, the 
exiftencein Paris, which we do nr doubl, of a faithlefs fet 
le, who have the affurance to avail themfelves of 
other men’s pena and to perfuade the world that they are 
their own. However, as there is confiderable ingenuity ma- 
nifefted in the ar rangement a the different parts of this ma- 
ine, as contained in his 
€ 
under our 
we fhall give the fubftance of 
the acc s, and leave the reader to ex- 
ercife his fkill in determining is himfelf fuch praGtical num- 
bers as this particular conftruction demands, which tafk will 
afford a eee of further mples : our t Heh a 
Plate VI. of cur feries, Sed Planetary Machine 
have given a ies of the fe€tion of all the a arian 
of this machine, wel bears aed refemblance to the 
in fig. }. 
rpetent - Iedlien of a brafs ae a together by the 
ars a,a, and fupported by a table 5% French feet in dia- 
bore not feen in the plate. In this frame are contained 
the wheels for giving motion to the Earth, Mars, Jupiter, 
Supiter’s moons; and Sat urn’s moons ; upon the upper 
plate of i {maller frame ,Y Y, fupported 
by the fhort pillars z, z, containing the wheels oe giving 
motion to Saturn and Georgian, (or Herfchel,) and above 
this {mall frame is another wheel for in 
moons of Georgian. 
cury have their wheelwork he 
fun, and the wheels for the fatellites are at the extreme end 
of the refpective arms, while fuch postions a oe mechanifna 
as she ak be feen sa n ip fg. 1. cay etached ftate 
e 
cea 
ee — plate 
he 
pean Dies sd and ay 
ita ae wh heal pacer na “the on d, befcre-mentioned, 
which is (hereiore called the annua wheel. 
ied horizontal diurnal arbor is fupported by the cock 
arked 13, and the arran 
aay wheel, G,\ 8 
may be called the flaw motion, 
ae 395% turns are made ina SA is Araceae rma 
iG, 
contiguous wheels to move loofely round their arb 
way round, but the clicks faft to ihe wheels catch. de. teeth 
of the parehees when going the other ied and attach them 
to their arbors refpe whenever the click of 
im 
chets having their teeth fo Ropes in oppofite ae@ican that 
they never oppofe each other’s ation, but, on the contrary, 
when one ceafes to act, at the inftant the handle retrogrades, 
the other Gag: and thus the pinion d continues its motion 
in the fame ion at all times, if the andle move at all ; 
ela 
motion Clea is fimple but in 
nious, and the r fays he introduced a contrivance for 
aaa all the to ‘bodies move backwards, when re- 
quired, as well as forwards, which cannot he done with the 
ratchet acting in the cna way ; but he has not thought 
proper to explain his method; though he fays that it is hy 
the ufe of the quick motion that the — motions are 
pie eu howeyer, 
m y be thus: 
the exterior end of t may be ‘lowered by a 
fliding motion of its Goanag piece n the teeth of Pinion 4 
are detached from wheel E, while yet the teeth of the con- 
trate wheel y wil] continue in action in pinion d by ae 
12 re) 
