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 proportionbetween 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 theduplicate 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 othersecondary planets
That they are influenced by a centripetal force directedtoward 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 thesun in the quarters, and diminished in the conjunction and opposition[p. 198]
The distance of the moon from the earth in the quartersand in the conjunction and opposition is altered by the sun[p. 200]
These irregularities in the moon’s motion varied by thechange of distance between the earth and sun[p. 201]
The period of the moon round the earth and her distancevaried by the same means[ibid.]
The motion of the nodes and the inclination of themoons orbit[p. 202]
The motion of the apogeon and change of theeccentricity[p. 218]
The inequalities of the other secondary planets deduciblefrom these of the moon[p. 229]
[Chap. 4.] Of comets
They are not meteors, nor placed totally without theplanetary system[p. 230]
The sun acts on them in the same manner as on theplanets[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 anothercomet in 75 years[p. 234]
Why the comets move in planes more different fromone 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 anattractive power, and that the force of the samebody on others is proportional to the quantity ofmatter 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 inthe sun and in all the planets, and therefore isthe same with gravity[p. 252]
That the attractive power in each of these bodies isproportional to the quantity of matter in the body attracting[ibid.]
That each particle of which the sun and planets arecomposed is endued with an attracting power, thestrength of which is reciprocally in the duplicateproportion 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 surfaceof the sun, the earth, Jupiter and Saturn; the respectivedensities of these bodies, and the proportionbetween 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, becausesome reflect one kind of light more copiously than therest, 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 theircolours depend.
Light is not reflected by impinging against the solidparts 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, andinflection of light.
Rays of different colours are differently refracted[p. 357]
The sine of the angle of incidence in each kind of raysbears a given proportion to the sine of refraction[p. 361]
The proportion between the refractive powers in differentbodies[p. 366]
Unctuous bodies refract most in proportion to theirdensity[p. 368]
The action between light and bodies is mutual[p. 369]
Light has alternate fits of easy transmission andreflection[p. 371]
The fits found to return alternately many thousandtimes[p. 375]
Why bodies reflect part of the light incident upon themand transmit another part[ibid.]
Sir Isaac Newton’s conjectureconcerning the cause of this alternate reflection andtransmission of light[p. 376]
The inflection of light[p. 377]
[Chap. 4.] Of optic glasses.
How the rays of light are refracted by a sphericalsurface 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 concaveglasses 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 thedifferent 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]