ORA 
ORT 
Oratava, 
Orbs. 
top of the pike in that illand, ; 
with obfervations made thereon, 
by 
the 
the 
aphelia, 
the angle of motion at the other of focus 
planet’s ellipiis - - h 
— An account of the appearance of Mercury paf- 
fing over the fun’s difk, on the 29th of Octo- 
ber, 3723; determining the mean motion, 
and fixing the nodes of that planet’s orb 
H 
Orbit. The curve afiigned by Caflini to planets as 
their orbit, confidcred and refuted Gregory , 
— - — The parabolic orbit for the comet of 1739, ob- 
ferved at Bologna - - Zanctti 
— A treatife on the precefiion of the equinoxes, 
and in general on the motion of the nodes, 
and the alteration of the inclination of the 
orbit of a planet to the ecliptick Silvahelle 
Orcades. An account of the current of the tides 
about the Orcades - - Anon . 
Ores. An examination of various ores in the mu- 
feum of Dr. W. Hunter Fordyce and Alchorne 
Organ. Letter on fome fuppofed imperfections in 
an organ - - Wallis 
Orkney. An abftraft from an account of the 
iilands of Orkney, by James Wallace 
Orrery. The phaenom'ena of Venus reprefented in 
an orrery made by Mr. James Fergufon, 
agreeable to the obfervations of Signior Bi- 
anchini - - - 
Orthoceratites. An account of a remarkable 
foffil orthoceratites - Wright 
Another account - Wright 
— An account of a rare fpecies of, found in Swe- 
den - - - Hi m/ el 
Oscillation. On the finding of the centre of of 
cillation - - ¥ ay lor 
Tranf. 
> 
Abridg. 
;■ x 3*3 
-658 
' XXIX 317 
V 2 148 
XI 683 
I 258 
# 
XXXIII 228 
VI 253 
XXIV 1704 
IV 206 
XLI 809 
VIII 215 
LXVIJI 385 
VIII 6139 
II 2 go 
LXIX 529 
XX 249 
I 612 
XXII 543 
XLIV 127 
X 95 
XLIX 670 
— 672 
L 692 
XXVIII 11 
IV 384 
Os 
