ORRERY. 
* period of the sth, viz. 48 12 27™ scs, the wheel c gives 
thotion to another fide arbor, by means of wheel d; and 
this laft arbor carries again two ae aa SS 
er of which, near Q, 
gain, janie $s arm, 
nd the excentric piece g, placed on the eis 
of bridge 15, and is counterpoifed by the weight ¢ 3 5 
long pinion, a, acts, like Georgian’s, above the large ae 
contrate wheel mn, and saga a fimilar acceleration to 
that of Saturn in Kind, ut not in quantity ; for the excen- 
are of different dimentiovs, and ae is placed in 
rection of its own line o 
‘the cake of wheel I, drives co arm by the pin 4, entering 
m ##, and the fhort pinion, 5, 
drives the contra 
in-1? 185 28™ 368, the period of tke firft fatellite of this 
planet ; the wheel attached to this contrate wheel, ¢, drives d, 
ona fide arbor, and wath it three more a on this common. 
arbor, each of which impels its fellow 2, 3, and 4 refpec- 
. tively in the periods of the 2d, 3d, and 4th fatellites. The 
little arms of all the fatellities are ‘comnieGed with as many 
tubes, taking their motions from the laft movin wheels, as 
feen in the drawing, without further defcription ; but it will 
have been remarked, that all thefe fecondaries in this ma- 
_ chine are made to move in the fame plane with that of the 
ecliptic, which in nature is the cafe with Jupiter’s only; 
confequently the motions of both 
tube of bridge 14, and impelled by the pia 2 of the bar 
attached to the tube of whee! H: this planet, con ae 
has an excentric motion in his orbit ; having no moons, 
requires only a fimple arm. ver Mars is placed the Earth’s 
annual arm with its. appendages, which are neceffarily on a 
fmall {fcale, and which the author has put in an enlarged 
fection on a feparate plate, containing the mechanifm for the 
earth’s parallelif m and diurnal rotation, the periodic mo- 
tion of the 
51 170 _ 25670 
“Telifn are : x 193 2566 
a difference alii the numerator and denominator of 
, in which fraction there is 
unity 3 or ‘part of the whole would be the annual 
Te o 
quantity of deviation from ftri& parallelifm ; aaa it. is eafy 
to fee, that the adoption of thefe e large nu umber would re- 
h sane ia its crore pro- 
n them; or other- 
greatly, and 
ing to the length a 
of o planetary arms, and the long pina “would by fuc h 
V. 
oO 
.femicircles of hae re{petive wheels. 
th 
-annual 
alteration become too much elongated for ae eereley in both 
reed the 
which hi 
other 
24 ae motion, thereby making it revolve, a partly by 
the ircul xis preferves 
its Salina by which circuit the fun apne to move re- 
pivots of an ard fixed axis allow the horizon circle to 
turn on them for effeCting the different degrees vs inclination. 
The moon’s monthly motion is taken from the fecond wheel 
of 48 hours by a train of two pinions, and as many wheels, 
feen in the a oe by the two cocks above the 
ram already faid that the fecond, or 
middle ale! of araliclts under the annual frame, has 
a vertical arbor, which we propofed to call the annual arbor: 
refts during her monthly motion in the ufual w gain 
the upper wheel on the annual arbor, which is “Teprefented 
in a line with wheel x, but which is actually on one fide of it, 
and in contact with it in the machine, gives motion to this 
its retpeCtive tube and attached arm, in their due periods. 
In this arrangement, the planets Us and Mercury, as alfo 
the Earth r orbits with equable 
ee dace 
al 
ar to have been adopted, is intended apparently to thew 
the nay of the contriver rather than the utility of its 
41 adopti 
