ORRERY. 
which all the other wheels are carried by the annual bar, as in 
the tellurian, which is taken from = pach when the ra cana 
s orbit, advance through the 
d, which, ac- 
cording to La L 
o tha t the error is nearly 
From the examination which has here been detailed of 
Martin’s planetary numbers, the reader, it is prefumed, w rill 
not think the inference unfair, if we affert that the various 
inaccuracies which have been oa ed out, fhew the pro- 
priety of abandoning th hefe numbers in future, and of fub- 
ftituting others which fhall exhibit the various motions more 
ae ully. 
ery for the seas of the Sun, Moon, Earth, and in- 
ae ee s, by the Rev. W. Pearfon.—During the time 
that Mr. Pearfon refided at the city of Lincoln, he withed 
to seedaae an orrery at a moderate expenfe, and conftrufted 
m numbers which might have fome ae etenfions to accu- 
racy, but not being a - ne is is wifh, after a cor- 
refpondence with an ment-maker in London on the 
fubje&t of his enue. i camel to try if he could not 
contrive an inftrument himfelf to be made under his dire@tion 
After fome confideration he 
his wheelwork. He found o 
adopt the annual train of Fergufon b me, he 
thought = accurate ; this train he tranfmuted into 
= x aX % x = == 365% 55 48™ 58%. The large wheel of 
300 formed plate that was graduated on its plane into a 
Saaripe {piral of days, an ecliptic circle, and a declination 
circle, and was ay rted by claw feet, but not at its centre. 
i 16 had the arbor for the diurnal handle, 
parallelifm a 
the centre ; to the under face of the annual box was - 
ep 
their arbors patty ng down Age h it ioe they a on the 
; the laft whe el of Me 
top, which, by it both the equation 
of the centre, the = of diftance, and the heliocen- 
tric latitude, as fee 3- Plate IV. 
achines, and elas a the article Equation Me- 
chanifm. "The arbor of the fun's latt wheel vated again 
a competent idea 
e fun, ant the 
other planets at propor rional aes while Venus alfo 
moved in her inclined orbit by means of her arm havi ing a 
at the fun’s ftem, and oie on an inclined graduated 
circle. 
Taste of the Trains &c. 
D 
eT , H. M. S. 
ne Earth’s 14 14 1 
wheels 300 x 46 * 33 365 5 48 58 
Its parallel- 120. 100 #f 
iin diiG } Too * Ing = yr rome revolution. 
Moon’s fy- 14 go 38 
nodic do. 300 oars 94 29 12 43 31 
Moon’s ano- 28 : 
mal. a6, a of a lunation 27 13 28 37 
Moon’s nod ica gas ; 
oon’s nodes a 35 38% 224 18 21 28 
Trop 63 40 96 
Y — ees EA 
of Venus Fey ae a0 224 16 42 7 
Do. of Mer- 15 79 
cury - i Pree I 87 23 16 44 
Sun’s rota- 30 27 
tion - } renee 97 25° 9 59 32 
Three pinions of 15 for the earth’s axis. 
Three pinions of 8 for the fun’s axis. 
Mercury’s excentric motion = x Sa = — revol. 
I 
Three dies of 30 for the moon’s phafes. 
e wheels were all put in motion by a common watch 
a by means of a pinion of 8 inferted on the 
Prieftley, a velatiy of Dr. 
in Glafgow, which orrery was made by 
Hare Be Glockmaker of Fallifax, in the fam me coun 
As we have een favoure with a defc 
inftrument b i 
t than to copy 
this defcription, to examine the eicdiaions ae by the 
contriver, 
