I N D E X.

Fixity, what, i. 27.

Flame , Difference between it and Fire, ii. 283 n.Florentine , Experiment with a Globe, i. 251 n.

Fluids, spherical Figure of, accounted for, i. 38 n.What, i. 249. Four Characteristicks of, illustrated,i. 249 n. Subtility of the Particles of, i. 251 n.Laws and Properties of, i. 250, Gravitate on oneanother, i. 252, Their Pressure, i. 254, AbsoluteGravity of, i. 254 n. Pressure upwards and down-wards equal, i. 255. Surface of, perfectly smoothi. 257. Figure of the Surface convex, i. 258.Why this Convexity does not appear in Fluids ofsmall Extent, i. 258 n. Pressure of a Vessel,what, i. 259. Easy Way of computing by Series,i. 260. Objection answered, ibid. Pressure againstthe Side of a cubical Vessel, what, i. 261. Uponthe Bottom of any Vessel proportional to the Altitudeonly, and why, i. 265, iffseq. Lateral Pressure,what, i. 262 n. Difference between Fluids andSolids, i. 263 n. Pressure on the Bottom of Vesselsestimated, i. 263 n. iffseq. General Theorem for,

i. 264. Pressure Centre of what, i. 265 n. Ex-actly balanced by a Force equal to the whole Pres-sure, ibid. Centre of, Pressure the fame as of Per-cussion, i. 266 n. Reason for trying them with theHydrometer, i. 280. Specific Gravity of, how de-termined, i. 285. Motion, to what owing, ii. 2.Natural Motion of, from Gravity, ii. 3. Rea-son for, ii. 3. The Particles of are solid Bodies,and observe the fame Laws with these, ii. 4 n. De-monstrated, ibid. Easily conveyed thro’ Syphons,

ii. 11. Velocity of a Spouting one, ii. 33 n. ThsForce of any projected Fluid estimated, ii. 35 n.Motion of caused by Attraction, ii. 91. Illustratedin the Tides, ibid. iff seq.

Fluidity accounted for, i. 32 n.

Fluxions , universal Method of determining Reflectionand Refraction, iii. 3 n.

Fly. • See Jack.

Flying, impossible in Man, ii. 155 n.

Focal Distance of Convex and Concave Mirrours, Rulefor finding, ii. 21.

E e ?, Foci,