THE
CONTENTS.

INTRODUCTION concerning Sir Isaac Newton’s
method of reasoning in philosophy————————pag. 1

Book I.

Chap. 1. Of the laws of motion
The first law of motion proved p. 29
The second law of motion proved p. 29
The third law of motion proved p. 31
Chap. 2. Further proofs of the laws of motion
The effects of percussion p. 49
The perpendicular descent of bodies p. 55
The oblique descent of bodies in a straight line p. 57
The curvilinear descent of bodies p. 58
The perpendicular ascent of bodies ibid.
The oblique ascent of bodies p. 59
The power of gravity proportional to the quantity of matter in each body p. 60
The centre of gravity of bodies p. 62
The mechanical powers p. 69
The lever p. 71
The wheel and axis p. 77
The pulley p. 80
The wedge p. 83
The screw ibid.
The inclined plain p. 84
The pendulum p. 86
Vibrating in a circle ibid.
Vibrating in a cycloid p. 91
The line of swiftest descent p. 93
The centre of oscillation p. 94
Experiments upon the percussion of bodies made by pendulums p. 98
The centre of percussion p. 100
The motion of projectiles p. 102
The description of the conic sections p. 106
The difference between absolute and relative motion, as also between absolute and relative time p. 112
Chap. 3. Of centripetal forces p. 117
Chap. 4. Of the resistance of fluids p. 143
Bodies are resisted in the duplicate proportion of their velocities p. 147
Of elastic fluids and their resistance p. 149
How fluids may be rendered elastic p. 150
The degree of resistance in regard to the proportion between the density of the body and of the fluid
In rare and uncompressed fluids p. 153
In compressed fluids p. 155
The degree of resistance as it depends upon the figure of bodies
In rare and uncompressed fluids p. 155
In compressed fluids p. 158

Book II.

Chap. 1. That the planets move in a space empty of sensible matter p. 161
The system of the world described p. 162
The planets suffer no sensible resistance in their motion p. 166
They are not kept in motion by a fluid p. 168
That all space is not full of matter without vacancies p. 169
Chap. 2. Concerning the cause that keeps in motion the primary planets p. 171
They are influenced by a centripetal power directed to the sun p. 171
The strength of this power is reciprocally in the duplicate proportion of the distance ibid.
The cause of the irregularities in the motions of the planets p. 175
A correction of their motions p. 178
That the frame of the world is not eternal p. 180
Chap. 3. Of the motion of the moon and the other secondary planets
That they are influenced by a centripetal force directed toward their primary, as the primary are influenced by the sun p. 182
That the power usually called gravity extends to the moon p. 189
That the sun acts on the secondary planets p. 190
The variation of the moon p. 193
That the circuit of the moons orbit is increased by the sun in the quarters, and diminished in the conjunction and opposition p. 198
The distance of the moon from the earth in the quarters and in the conjunction and opposition is altered by the sun p. 200
These irregularities in the moon’s motion varied by the change of distance between the earth and sun p. 201
The period of the moon round the earth and her distance varied by the same means ibid.
The motion of the nodes and the inclination of the moons orbit p. 202
The motion of the apogeon and change of the eccentricity p. 218
The inequalities of the other secondary planets deducible from these of the moon p. 229
Chap. 4. Of comets
They are not meteors, nor placed totally without the planetary system p. 230
The sun acts on them in the same manner as on the planets p. 231
Their orbits are near to parabola’s p. 233
The comet that appeared at the end of the year 1680, probably performs its period in 575 years, and another comet in 75 years p. 234
Why the comets move in planes more different from one another than the planets p. 235
The tails of comets p. 238
The use of them p. 243 244
The possible use of the comet it self p. 245 246
Chap. 5. Of the bodies of the sun and planets
That each of the heavenly bodies is endued with an attractive power, and that the force of the same body on others is proportional to the quantity of matter in the body attracted p. 247
This proved in the earth p. 248
In the sun p. 250
In the rest of the planets p. 251
That the attractive power is of the same nature in the sun and in all the planets, and therefore is the same with gravity p. 252
That the attractive power in each of these bodies is proportional to the quantity of matter in the body attracting ibid.
That each particle of which the sun and planets are composed is endued with an attracting power, the strength of which is reciprocally in the duplicate proportion of the distance p. 257
The power of gravity universally belongs to all matter p. 259
The different weight of the same body upon the surface of the sun, the earth, Jupiter and Saturn; the respective densities of these bodies, and the proportion between their diameters p. 261
Chap. 6. Of the fluid parts of the planets
The manner in which fluids press p. 264
The motion of waves on the surface of water p. 269
The motion of sound through the air p. 270
The velocity of sound p. 282
Concerning the tides p. 283
The figure of the earth p. 296
The effect of this figure upon the power of gravity p. 300
The effect it has upon pendulums p. 302
Bodies descend perpendicularly to the surface of the earth p. 304
The axis of the earth changes its direction twice a year, and twice a month p. 313
The figure of the secondary planets ibid.

Book III.

Chap. 1. Concerning the cause of colours inherent in the light
The sun’s light is composed of rays of different colours p. 318
The refraction of light p. 319
320
Bodies appear of different colour by day-light, because some reflect one kind of light more copiously than the rest, and other bodies other kinds of light p. 329
The effect of mixing rays of different colours p. 334
Chap. 2. Of the properties of bodies whereon their colours depend.
Light is not reflected by impinging against the solid parts of bodies p. 339
The particles which compose bodies are transparent p. 341
Cause of opacity p. 342
Why bodies in the open day-light have different colours p. 344
The great porosity of bodies considered p. 355
Chap. 3. Of the refraction, reflection, and inflection of light.
Rays of different colours are differently refracted p. 357
The sine of the angle of incidence in each kind of rays bears a given proportion to the sine of refraction p. 361
The proportion between the refractive powers in different bodies p. 366
Unctuous bodies refract most in proportion to their density p. 368
The action between light and bodies is mutual p. 369
Light has alternate fits of easy transmission and reflection p. 371
The fits found to return alternately many thousand times p. 375
Why bodies reflect part of the light incident upon them and transmit another part ibid.
Sir Isaac Newton’s conjecture concerning the cause of this alternate reflection and transmission of light p. 376
The inflection of light p. 377
Chap. 4. Of optic glasses.
How the rays of light are refracted by a spherical surface of glass p. 378
How they are refracted by two such surfaces p. 380
How the image of objects is formed by a convex glass p. 381
Why convex glasses help the sight in old age, and concave glasses assist short-sighted people p. 383
The manner in which vision is performed by the eye p. 385
Of telescopes with two convex glasses p. 386
Of telescopes with four convex glasses p. 388
Of telescopes with one convex and one concave glass ibid.
Of microscopes p. 389
Of the imperfection of telescopes arising from the different refrangibility of the light p. 390
Of the reflecting telescope p. 393
Chap. 5. Of the rainbow
Of the inner rainbow p. 394
395 398 399
Of the outter bow p. 396
397 400
Of a particular appearance in the inner rainbow p. 401
Conclusion p. 405

ERRATA.

PAGE 25. line 4. read In these Precepts. p. 40. l. 24. for I read K. p. 53. l. penult. f. Æ. r. F. p. 82. l. ult. f. 40. r. 41. p. 83 l. ult. f. 43. r. 45. p. 91. l. 3. f. 48. r. 50. ibid. l. 25. for 49. r. 51. p. 92. l. 18. f. A G F E. r. H G F C. p. 96. l. 23. dele the comma after {⅓}. p. 140. l. 12. dele and. p. 144. l. 15. f. threefold. r. two-fold. p. 162. l. 25. f. {⅓}. r. {⅞}. p. 193. 1. 2. r. always. p. 199. l. penult. and p. 200. l. 3. 5. f. F. r. C. p. 201. l. 8. f. ascends. r. must ascend. ibid. l. 10. f. it descends. r. descend. p. 208. l. 14. f. W T O. r. N T O. In fig. 110. draw a line from I through T, till it meets the circle A D C B, where place W. p. 216. l. penult. f. action. r. motion. p. 221. l. 23. f. A F. r. A H. p. 232. l. 23. after invention put a full point. p. 253. l. penult. delete the comma after remarkable. p. 255. l. ult. f. D E. r. B E. p. 278. l. 17. f. ξ τ. r. ξ π. p. 299. l. 19 r. the. p. 361. l. 12. f. I. r. t. p. 369. l. 2, 3. r. Pseudo-topaz. p. 378. l. 12. f. that. r. than. p. 379. l. 15. f. converge. r. diverge. p. 384. l. 7. f. optic-glass. r. optic-nerve. p. 391. l. 18. r. as 50 to 78. p. 392. l. 18. after telescope add be about 100 feet long and the. in fig. 161. f. δ put ε. p. 399. l. 8. r. A n, A x. &c. p. 400. 1. 19. r. A π, A ρ. A σ, A τ. A φ. p. 401. l. 14. r. fig. 163. The pages 374, 375, 376 are erroneously numbered 375, 376, 377; and the pages 382, 383 are numbered 381, 382.