I N D E X.

Rise of Fluids, by what caused, ii. 2.

Rotation , diurnal, of the Earth, ii. 97 n.

Rowley, Mr. his large Orrery, iii. j68 nRowning Mr. Inventor of the Compound Barometer,11. 128 n. *

Rule, general concerning Pumps, from the Theorem54 n - For finding the focal Distances of convexand concave Mirrours, iii. 21. For finding un ; *sally the Focus of a Lens, iii. 25. Of phifosophiz"ing, 1. 2 V/r-. r pmz ~

S.

O-Æk of a Wind-Mill in the Form of elliptical Sec-tors, ii. 2x7 n. Best Position of, i, 219. Theory,&c. of, i. 220 n. ’

Sailing, the only true Way of, iii. 306 n.

Satellites of Jupiter, Times and Distances of their Re-volution, iii. 120 fe t seq. First discovered by Gali-leo, iii. 123 n. Phases of illustrated, iii. i24 n. Re-volve about their own Axes, ibid. Noble Problemssolved by, iii. 125 n.

Saturn, his five Moons and stupendous Ring describediii. 124. Different Phases of the Ring, iii. 127 n.Savery, Captain, Account of his Fire-Engine, ii. 74 n.Scale, diatonic, o; Mustek, what, ii. 254.

Screw , what, st 1 66 . Force of, i. 173 n. Archime-des’s, for raising Water, described, ii. 66 n.

Sea, what, iii. 283.

Sea-Gage, Description of, ii. 139 n. How used, ibid.& seq. New Form of for Depths described, ii."

141 n.

Seasons, Variety of, whence, iii. 178, Various Ap-pearances of, how caused, ii. 179 U seq. Shewnby the Orrery, iii. 179 &seq. Accounted for bythe Earth’s Motion in its Orbit, iii. 180.

Settion of the human Eye, iii. 27 n.

Semitones, fee Scale of Mustek.

Semi-tycbonic SyRem, what, iii. 101 n.

Shadow, dark, how estimated, iii. 198 n. Partial feePenumbra.

Sharps, fee Tune.

Shortsighted , fee Purblind.

Simple Ratio, what, i. 6 n,

5 Sine.