C I 1 
 
 Of NATURAL PHILOSOPHY. 
 
 I. 
 
 A L L the fubje&s of human knowledge 
 are comprehended under the general 
 names of body and mind. 
 
 Animals confift of both; and from their 
 motions and the motions and changes produ- 
 ced by them, among the bodies around them, 
 it is manifeft, that there is a connexion, how- 
 ever infcrutable, between body and mind. 
 They mutually affeCt each other. 
 
 Motions and changes are perpetually go- 
 ing on, in the material world, independent 
 of the interpofition of animals. Thefe are 
 perceived as effe&s, necefTarily implying cau- 
 fes by which they are produced. — Thexaufe* 
 are named thu' unknown. — Weight.-: — Heat. 
 — Electricity. 
 
 Thefe caufes are obferved to operate regu* 
 larly. 
 
 Whatever are perceived of the bodies which 
 compofe the material world : their iituations, 
 ^ / ^ > ynQtions, 
 
m*rt^Tre ( 
 
 motions, changWffrc called natural appearances 
 or phenomena ; their caufes, natural caufes* 
 the rules which thefe caufes obferve, in the 
 exertion of their efheaev, laws of nature. / 
 
 When, contemplating the works of na- 
 ture, we remark the adjufhnent and fubier- 
 wiency of things : the tendency of fome to 
 fupport or deftroy others ; we perceive mani- 
 feft defigns and deftinations, and are irrefifti- 
 bly led to refer natural caufes to the power, and 
 die laws of nature to the will of intelligence, 
 fu peri or to human. Power.— Will. —Nature : 
 .efficient, and final caufes. — Natural Hffiory. 
 **— -Natural Theology. — Natural Pliilofophy. 
 
 The Scope of Natural Pliilofophy is, 
 I. To afeertain the laws of nature. 2. To 
 explain the phenomena of nature. 3. And 
 to dire& the application of the knowledge of 
 thefe to the improvement and invention of 
 arts, for the accommodation of life; and 
 to the advancement of other fciences. 
 
 II. 
 
 Man begins to acquire the knowledge of 
 nature, when he begins toexift. — 1. He enters 
 the world poflefled of inftinclive arts, and 
 capable of perception, of intuitive knowdedge, 
 and of reafoning. — 2. Prompted by neceffity, 
 
 he 
 
C 3 ? 
 
 he encreafes his knowledge; that his power 
 may be enlarged. 3. Prompted by acciden- 
 tal motives, he advances in knowledge, and 
 in power . — Arts and Sciences. 
 
 The connection between caufe and effect, 
 tho’ not perceived, is afeertained by the laws 
 of perception, and by experience and reason- 
 ing. 
 
 A riling fcale of connections may be tra- 
 ced. 1. Artificial words* or figns, and their 
 meaning. 2. Inftindtive exprellions of ien- 
 timent, and their meaning. Or natural figns, 
 and things fignified. — Natural Language . 
 
 3. Perceptions, and the fenfible qualities of 
 external objects. 4. Motions of bodies and 
 the affedtions of matter. 5. Many pheno- 
 mena are perceived as effedts, whofe caufes 
 are not fuggefted-. 
 
 Laws of nature are inveftigated from a few 
 phenomena carefully examined : from the 
 laws, as principles of philofophy, other phx- 
 nomena are explained. — Arts are o>:ten im- 
 proved, fomethnes derived from feience, 
 
 ITT. 
 
 There is but one genuine method of teach- 
 ing fcicnce, which mu ft be formed on the 
 A 2 model 
 
ul 
 
 4 3 
 
 
 model of the natural progrefs of the mind in 
 it’s acquifitions of knowledge. — Analyfis.— . 
 Syntheiis. 
 
 Of the DIVISION and ARRANGE- 
 MENT of the SUBJECT. 
 
 I. 
 
 Some Philofophers have exceeded in ab- 
 ftraft fpeculation. Others, contemplating 
 natural objects intirc, as they exift, have too 
 much negledted abftrattion. 
 
 Thefe are two extremes, which fhould both 
 be avoided. — There is no middle courfe. — • 
 The remedy lies in alternating thefe two. 
 
 II. Nature 
 
 -- 
 
 
 p. 
 
 M 
 
 :v 
 
 !®| 
 
 n 
 
 w HEN an extenfive fubjeft of fcience is 
 
 to be examined, the limited capacity 
 of human apprehenfion requires a limitation 
 of attention. The attention is often with- 
 drawn from fome things, and limited to o- 
 thers, which are infeparable. This limitation 
 is called Abftra&ion ; and is pra&ifed by all 
 men. Abftradt terms are frequent in com- 
 mon language, abundant in the language of 
 every fcience. 
 
 -rjlSK 
 
 fa 
 
 P 
 
 i\ 
 
 'don 
 
 Hu 
 
 ;li 
 
 zk 
 
 
C 5 1 
 
 u 
 
 II. 
 
 Nature is an extenfive fubjeft, varioufly 
 divifible. i. Genera; fpecies ; individual. 
 
 2. Ends; means. Supreme; fubordinate. 
 
 3. Caufe ; effect. 
 
 The rule of divifion is to be derived from 
 the purpofe. The three ways, fpecified, of 
 dividing nature, are fuited to the purpofes of 
 1. Natural Hiftory. 2. Natural Theology. 
 
 3. Natural Philofophy. 
 
 III. 
 
 Effefts only appear. Caufes are fuggefted, 
 with various degrees of evidence, as the know- 
 ledge of them is neceflary, ufefui, convenient. 
 
 — 1. Intuitive conviction. 2. Conjecture. 
 
 3. Confirmation by experiment. — Experimen- 
 tal Philofophy . 
 
 The phenomena of nature proceed from 
 
 1. The independent properties of bodies. 
 
 2. AfFeCtions of matter- 3. The feniible 
 qualities of objeCts. 4. Higher caufes. 
 
 The independent properties of a body are 
 thofe found in it when examined by itleli*. 
 Such are exteniion, divifibiiity, impenetrabb 
 
 lity. 
 
 A 3 
 
 ns 
 
U 6 1 
 
 Affe Elions of matter are thofe qualities a - 
 feribed to bodies, by which they are faid to 
 move, and to produce changes on each other: 
 thofe powerful agents in nature : thofe effi- 
 cient caufes, to which, tho’ unknown, we give 
 
 names. Cohefion. Magnetifm. — ■ 
 
 Ele&ricity. 
 
 Senfible qualities are thofe by which ob- 
 jects are related to us, and affeft our fenfes. 
 Independent properties, and affections of mat- 
 ter are fenfible qualities, which are perceived, 
 or fiiggefted by our fenfations. But thofe to 
 which the meaning of the term is here re- 
 ftriCied are only implied in our fenfations : 
 what they are not being luggefted, but left as 
 matter of invefligation. — Heat. — Tafte. 
 
 Higher , or more general caufes, are thofe 
 to which fome of the others may be referred, 
 as effects. 
 
 When our attention is limited to the in- 
 dependent properties, all is ftill, inactive, life- 
 left. 2. When extended likewife over the af- 
 
 fections of matter, the material world becomes 
 a bufy, animated feene ; fuggefting power, in- 
 telligence, deiign, fuperiqy beings. — 3. Man 
 is interefted in this feene. He is connected 
 with the material world by organs of fenfe ; 
 
 bv 
 
I 7 ] 
 
 u 
 
 by means of which he perceives external ob- 
 jects and their qualities. 
 
 Scnfible qualities are not the immediate 
 caufes of perception. Several other caufes 
 are interpofed, like fo many links of a chain. 
 — Perception. — Senfation. — Imprefllon.— 
 Condition of the organ. — Motion. — Senhble 
 quality. — Sometimes a Medium . 
 
 In different inftances of perception, the at- 
 tention is limited to different links of the 
 chain, while others are overlook’d. In ex- 
 amining the independent properties, we ab- 
 ftraCt from the intermediate links. 
 
 IV. 
 
 Natural fubftances are diverfffied by a va- 
 riety of affections, and fenffble qualities, and 
 their modifications. Whereas the indepen- 
 dent properties are common to all the parts 
 of the material world. When, therefore, 
 we fhall have examined thefe, we ffiall be ad- 
 vanced in the knowledge of the whole. 
 
 
 Of 
 
Of the I N D E P E N D E N T PRO- 
 PERTIES of BODIES. 
 
 I. 
 
 i. T7 Xtension: in which are implyed 
 2. Figure. And 3. Divifibility. — • 
 
 Space. 
 
 4. Impenetrability. — Denfity . — Quantity 
 of matter. — 5. Inertia. — Not necefflirily con- 
 nected with the other four. — Proportioned to 
 the quantity of matter. — Prefumed univerfal, 
 from general indudtion. — 6. Weight. Whe- 
 ther an independent property, or affefbon, 
 will appear in it’s proper place. 
 
 Matter is an abftradt term. 
 
 II. 
 
 Extenhon is the fubjedl of Geometry. 
 Number of Arithmetick . 
 
 Both of Algebra. 
 
 Some fkill in thefe abftra£l fciences, is ne- 
 ceflary as preparatory to the ftudy of other 
 branches of Natural Philofophy, For, being 
 
C 9 3 
 
 the moft general, they are involved in the o- 
 thers, and often referred to. And from them 
 is borrowed a method of exprefling meafura- 
 ble quantities of every kind : a fcientific 
 branch of language. 
 
 Ill* 
 
 Meafurable quantities, of every kind, are 
 exprefied by numbers, fymbols, lines. 
 
 A quantity which varies at the fame rate 
 with each of other two, i9 called a compound 
 quantity , Such are exprefied by produ&f* 
 
 re&angUf' 
 
 The relation of quantities, which vary at 
 the fame rate, is exprefied by (z =:) equality. 
 Such are often juftly fubftituted in reafon* 
 ing. 
 
 A quantity which varies directly as one, 
 and inverfely as another, is exprefied by a 
 fraction. 
 
1 
 
 
 OF THE 
 
 AFFECTIONS of MATTER in general; 
 
 PRESSING POWERS. 
 
 HE ftrength of animals, weight, and the 
 
 affc&ions of matter, agree in thefe two 
 things. That they prefs bodies to move ; 
 and that they proceed from the power of im- 
 material agents. They are, therefore, called 
 prelllng powers, or fimply powers. — Attrao - 
 tion, — Repulfion . 
 
 The effects of powers are i . To ba* 
 lance each other. 2. To move bodies.. 
 
 O R O F 
 
 I. 
 
£ a ] 
 
 Of the BALANCE of POWERS. 
 
 I. 
 
 I N the firft place, laws are to be inveftigated 
 from the phenomena, by analyfis. 
 
 II. 
 
 Prefiure and refiftance are, to us, the 
 fame ; for frequently undiftinguilhable. 
 
 Therefore equivalent, equal and oppofite. 
 
 A ft ion . — Re -aft ion . 
 
 Power is transferable to different points, 
 by ropes and rods. 
 
 III. 
 
 Heft is a proof of equality of prefiure. 
 
 Preflu re is a compound quantity; analy- 
 fed into intenfity and quantity of power. 
 
 IV. 
 
 Three powers proportioned, and parallel 
 to the fides of any parallelogram will balance. 
 
 ■ When a power is obliquely refilled, it is 
 rcfolved into two. One in diredl oppofition, 
 and another perpendicular, to the refifiance. 
 
 C H A- 
 

 MECHANICS. 
 
 PART I. 
 
 I. 
 
 I N the fecond place, phenomena are to 
 be explained from the inveftigated laws. 
 
 II. 
 
 Of the center of gravity .'—Center of Mo- 
 tion. — Inclined plane. 
 
 III. 
 
 Power. Weight. Machine. 
 
 The power and weight are not, properly, 
 in oppofition ; but are two powers confpiring 
 againft a third, which is oppofed to their joint 
 effort. 
 
 Of limple machines. i . The Lever . 
 
 2. Others reduced to the lever. — Wheel and 
 pinion. — Pulley. — Barrel arid handfpokes. 
 — Axis in pcritrochio. — 3. The Inclined 
 plane. — 4. Others reduced to the inclined 
 plane, — Screw, — Wedge. 
 
 Of 
 
[ 13 3 
 
 IV. 
 
 Qf compound Machines . 
 
 V. 
 
 In the third place, fcience is to be applied 
 to the improvement of art. 
 
 The dodtrine of the balance of powers is 
 of ufe, in afcertaining the ftrength, which 
 ought to be given to every kind of fupports. 
 Pillars ; piers ; arches - 9 beams ; members of 
 machines. 
 
14 1 
 
 Of motion. 
 
 I. 
 
 M OTION. Space. Time.— 
 
 Velocity : uniform ; accelerated ; re- 
 tarded. Their meafures, and expreffions. 
 
 Abfolute and relative. Apparent and 
 
 real. — 
 
 Quantity of motion. — Force: inherent, 
 
 impreft.— ^Impulfc..— -Rcfiftance .“ -A ction.-** 
 
 Re-a£tton, 
 
 II. 
 
 Of the laws of motion, 
 
 III. 
 
 Of the harmony between the laws of mo* 
 tion, and thofe of balancing powers. 
 
 PHAENO 
 
£ *5 1 
 
 U 
 
 PHAENOMENA explained from the 
 LAWS of MOTION. 
 
 I. 
 
 F the congrefs of bodies. 
 
 II. 
 
 Of the defeent, and afeent of heavy bo- 
 dies, in vertical lines. 
 
 III. 
 
 Of the defeent and afeent of heavy bodies 
 on inclined plane3. 
 
 IV. 
 
 Of pendulums. 
 
 V. 
 
 Of projectiles. 
 
 VI. 
 
 Of central forces. 
 
< 
 
 t fr 6 1 
 
 Of the AFFECTIONS of MATTER 
 
 in particular. 
 
 P Ressing powers agree in that they all 
 alike obey the general laws of balance, 
 and of motion. But they are diftinguilhed 
 by being Separately Subjected, each to it’s own 
 
 particular laws, 
 
C 17 ] 
 
 u 
 
 Of GRAVITATION. 
 
 PART I. 
 
 \ 
 
 I. 
 
 T H E lines in which bodies prefs down- 
 ward, by their weight, (vertical, or 
 plumb-lines,) are inclined to each other. — 
 Hence may be inferred. 
 
 That the earth is a globe. And 
 
 That gravitation is an affc£tion of matter. 
 
 II. 
 
 The figure of the earth is confirmed by 
 the explanation of phenomena. 1 . A fiiip, 
 failing in any one direction furrounds it. 
 2. To the people on board, the higher parts 
 of tall obje&s, to which they approach, come 
 firfi in fight ; and the lower parts of thofc, 
 from which they recede, are firfi: intercepted 
 from their view. 3. If the courfe be eaft, 
 the rifing, and fetting of the heavenly bodies, 
 are accelerated ; if weft, retarded. 
 
 B ^ ,Opi-ITSI- 
 
3 
 
 PHYSICAL ASTRONOMY. 
 
 I 1 A R T I. 
 
 I. 
 
 the diurnal motions. 
 
 II. 
 
 Of the annual motions. 
 
 III. 
 
 Of the folar fyftem. 
 
 IV. 
 
 Of the univerfal fyftem. 
 
1 9 [ 
 
 Of GRAVITATION. 
 
 PART II. 
 
 T H E moon gravitates to the earth. — 
 Hence it is inferred, That 
 
 The intenfity of gravitation is greater, in 
 proportion as the fquare of the diftance is 
 left. And hence the Copernican fyftem is 
 eftabliflied. 
 
 PHYSI- 
 
2 
 
 PHYSICAL ASTRONOMY. 
 
 PART II. 
 
 G ravitation is the power, that retains 
 the primary planets, circulating in or- 
 bits round the fun ; and the fecondary 
 round their primary. 
 
 Of comets. 
 
 Of the fixt flars.— And univerfal fy* 
 ftem. 
 
*t 21 3 
 
 Of GRAVITATION. 
 
 PART III. 
 
 G ravitation to the center of a fphere 
 arifes from gravitation towards each 
 particle of it. 
 
 All the particles of matter gravitate mutu- 
 ally, with forces varying with the diftances. 
 
 The law of this variation is deduced from 
 the law of gravitation to the center of a fphere. 
 •—And is the fame. 
 
 Of 
 
 
cy- * 
 
 0£ COHESION. 
 
 PART I. 
 
 C ^Ohesion may be confidered, in the firft 
 J place, only as a power refitting any 
 force applied to feparate the parts of bodies ; 
 or to move them feparately. 
 
 The difference of bodies, arifing from the 
 difference of ttrength, or intenttty with which 
 their parts cohere, is a difference in degree 
 only. Bodies are othenvife greatly diverfi- 
 fied by different modifications of cohefion* 
 
 This variety arifes from the degrees and 
 combinations of i. Hardnefs. 2. Elafticity* 
 3. Fluidity. 4. Softnefs. 
 
I *3 3 
 
 Of HARDNES 6. 
 
 r 
 
 Of ELASTICITY. 
 
 Of FLUIDITY. 
 
 Of the P R E S S U R E of FLUIDS, 
 O R 
 
 HYDROSTATICS. 
 
 Of the MOTION of FLUIDS, 
 o R 
 
 HYDRAULICS. 
 
 Of 
 
■J / 
 
 l j 24 3 
 
 Of ELASTIC FLUIDS. 
 
 O R 
 
 PNEUMATICS. 
 
 Of SOFTNESS. 
 
 Of the CHANGES of M O T I ON 
 from refitting MEDIA. 
 
 Of FRICTION. 
 
 MECHA- 
 
C 25 3 
 
 M E C H A N I C S, 
 
 PART II. 
 
 O F the refiftances arifing from the mo- 
 tion of machines. Perpetual mo- 
 
 tion. 
 
 Of the proportion betwixt the power and 
 weight, requifite to produce the greateft ef- 
 fect by machines. — Maximum . 
 
 C 
 
 hi E C II A- 
 
J 
 
 MECHANICS. 
 
 part III. 
 
 I. 
 
 o I‘ practical Ikill in machinery. 
 
 II. 
 
 Of examination of machines, 
 
 III. 
 
 Of contrivance of machines. 
 
 IV. 
 
 Of the cultivation of mechanic genius. 
 
I 27 3 
 
 COHESION. 
 PART II. 
 
 , ; . > 
 
 ^npHEsioM washes to tt dUtenee. 
 
 Of ELECTIVE ATTRACTIONS. 
 
 Of MAGNETISM. 
 
 C a 
 
 Of 
 
 
] 
 
 Of ELECTRICITY. 
 
 I. 
 
 TjYPCTHESIS. i. The phenomena of 
 electricity are produced by the affeCtions 
 of a particular fluid. 2 . The particles of 
 
 which attract each other at very fmali diftan- 
 rnJ. r/nvl m great* * Ulfrww, And 
 3» r lhis fluid has various affinities to other 
 fubftances, 
 
 II. 
 
 Of the elective attractions, or affinities of 
 the eleCtric fluid. 
 
 III. 
 
 Of the motions of electricity. 
 
 IV. 
 
 EleCtricity is perceived by every fenfe. 
 
 V. 
 
 Of the phenomena explicable from the 
 doCtrine of electricity. 
 
 VI. 
 
 Of the ufes of the knowledge of elcCtri- 
 city. 
 

 [ 29 1 
 
 Of SENSIBLE QJJ A L I T I E S. 
 
 every inftance of perception. And 
 the attention is limited to one or another, as 
 interefting. 
 
 The attention is limited fometimes to one, 
 fometimes to another, in the fame inftance. 
 ■ Hence the ambiguity of many words. 
 
 From thofc circumftanccs of objefts, which 
 are perceived, we learn to infer others, which 
 arc not perceived. — Hence perceptions are di- 
 ftinguilhed into original and acquired. — Ha- 
 bits. — Habits of inattention. 
 
 Organs of fenfe. — Nerves. — Senforium. 
 
 ^ Different qualities are explored by the fame 
 
 ANY links are overlook'd in, almoft, 
 
 fenfe. And the fame quality by different 
 fenics. 
 
 C 3 
 
 
 
 Of 
 
Of T O U C H. 
 
 T HE properties, affections, and conditions 
 of objeCts, which qualify them to 
 make impreffions on the organ of touch, are 
 magnitude, figure, impenetrability, vis infita, 
 motion. Minimum fenfibile. 
 
 Of TASTE, SMELL, and fome other 
 
 SENSES. 
 
 r ) ODIES are qualified to excite the fenfa- 
 J tions by their eleCtive attractions. Which 
 are not explored, but inferred. 
 
 Pleafure Pain . — Appetite . — Involunta- 
 ry motion. 
 
[ 3 1 ] 
 
 u 
 
 Of HEAT and COLD. 
 
 I. 
 
 T HE word, Heat, fometimcs ftgnifies a fcn- 
 fation, fometimes a quality. The qua- 
 lity is not perceived, but it is a fubject of in- 
 veftigation. 
 
 Heat is loft, and acquired by communica-» 
 tion. 
 
 Quantity, — Intenfity, — Degrees, of heat. 
 
 Degrees are meafured by the expanfton of 
 metals, and of fluids. — Thermometers . 
 
 II. 
 
 The fenfations, beat, and cold are excited, 
 when the quality heat is communicated to, or 
 from the organ. Heat when to, cold when 
 from. 
 
 III. 
 
 Heat is generated by friction, and by inte- 
 ftine motions . — Animal heat . 
 
 IV. Of 
 

 !1 
 
 
 32 ] 
 
 IV. 
 
 Of the effects of heat. 
 
 V. 
 
 Of the phenomena produced by heat. 
 
 VI. 
 
 Of the arts depending on the management 
 •f heat. 
 
 Of HEARING. 
 
 I. 
 
 w 
 
 7 HAT qualifies objects to excite the 
 
 fenfation of found, is a fubject of m- 
 veftigation. Suggefted to be adtion. — And a 
 medium is inferred. 
 
 II. 
 
 Of the medium of found. 
 
 III. 
 
 Of the affections and modifications of 
 found. 
 
 IV. 
 
 Of language. — And mufic, 
 
 
 
 Of 
 

 t 33 3 
 
 u 
 
 Of S E E I N G. 
 
 I. 
 
 T # 
 
 HE qualities perceived by fight are mag* 
 
 figure* 
 
 Of the places of fenfiblc objects* 
 
 A medium is inferred ; and many of the 
 laws of light are inveftigated, by all men. 
 
 II. 
 
 Of the propagation of light in right lines. 
 
 Ray. — Pencil. — Beam. — Luminous, 
 Shining. — Illuminated. 
 
 Radiation. — Reflection. 
 
 III. 
 
 Of the reflection of light. 
 
 IV. 
 
 Of the refraCtion of light. 
 
 V. Of 
 
Of vifion. 
 
 34 3 
 
 V. 
 
 VI. 
 
 Of colours. 
 
 VII. 
 
 Of the inflection of light. 
 
 VIII. 
 
 Phenomena explained. 
 
 IX. 
 
 Of optical arts, and infiruments. 
 
 X. 
 
 Of light. — Heat. — Fire. 
 
 
 
 Of 
 
t ' 35 1 
 
 u 
 
 Of H I G H E R CAUSES. 
 
 TK7 HEN particular efficient caufes, and 
 J laws of nature, deduced from the 
 ■phenomena, are traced further; they are 
 found to flow from others, more general and 
 fewer, as m tracing the branches of a tree 
 from the twigs towards the trunk. But uni! 
 
 lone n0t ieKChCd ' n tradng efficiem cauies a- 
 
 j n l Hke “ ng ° f n ' Vdl Caufe Is 
 
 into - 
 
 Final and efficient caufes, confidered toge- 
 
 will" of” f °n nd t0 ^ Unked in the P° wer ‘^d 
 f intelligent beings: the perception of 
 
 \ lgn exccut ed, furnifliing evidence of the 
 xifttncc, power, and other attributes of a 
 ddigner. 
 
 '^"^ N T> . , 
 
Partial contemplation of nature introduce* 
 the belief of many Gods. 
 
 The unity of nature proves the unity of 
 God. 
 

ft V o 
 
 \ 
 
 % 
 
 O J4>G3f