374 Rev, Mr, Emmet t on the [NoV. 



To suppose every chemical change susceptible of mathematical 

 demonstration would be extravagant ; but that the Uwfe of action 

 may be made out may be fairly supposed ; it receives' the sanc- 

 tion of the immortal Newton, than whom a more competent 

 jud^e never existed, although chemistry had scarcely begun to 

 assume the form of a science in his days : his opinion (and the 

 opinion of such a man ought to have great weight), ri^l^be 

 collected from the following part of the preface to his 'Prih(>i[Tia: 

 — " Utinam csetera naturae phaenomena ex principiis mem^hatiicis 

 eodem argumentandi generi liceret. Nam multa ra^ movent, ut 

 nonnihil suspicer ea omnia ex veribus quibusdam pendere posse, 

 quibus corporum particulae per causas nondum cognitas, vel in 

 se mutuo impelluntur, et secundum figuras regulares coheerenti 

 vel ab invicem fugantur et recedunt; quibus viribus ignotis> 

 philosophi hactenus naturam frustra tentariint. Spero autem 

 quod, vel huic philosophandi modo, vel veriori alicUi principia 

 hie posita lucem aliquam praebebunt." • <,hnii 



Analogy 1. — The most inflammable bodies hav^ the letti^lfo*ei 

 of attraction to the earth. ''^''' .<.yu.quK>j ^d yjiy/5iT> ortioeq^ 



In a former communicatibn if d6ttiiS^<^trateft^t!Wit^tlftl'^ftitt€t^ 

 of a particle of any simple substance is proportional to 



\/ sirS^~~~~!ft7 ' ^^^ body being in its piosit,de|;s,e solid stai^^ 

 also, that if the force of attraction of an ultimate particle of 

 matter belong to the entire mass of the atom, the intensity of its 

 force of gravity is proportional to its specific gravity, if the parti- 

 cles of solids be always similarly situated ; but that if it belong 

 to the surface only, to which opinion I incline^ for many cogent 

 reasons, the same force is proportional to specific gravity x 



diameter of a particle, or to its equal \/ | atomic weight X {spe- 

 cific gravity^ [. By this attraction I do not understand the 



entire gravitation of a particle, which is the product of the inten- 

 sity of the force, and the square of the diameter, or cube of the 

 diameter, according as the force belongs to the surface or t,he 

 solid content of an atom ; but the intensity only of the force,, o,ir, 

 as it may be called, the density of a particle. The following 

 table gives the force of some of the chief undecompounded sub- 

 stances; the atomic numbers are from Brande's Manual. The 

 gaseous bodies ought to be included, but at present the ^ataare 

 insufficient. '" ^t^ 



Force. 



Gold 78-3773 •^» 



Silver 52-6365 ''^ 



Copper 39-5736 



Iron 34-6054 



Lead 55-0248 



Tito, tir*^'* ^t^Mii kt'* »• • •^•* ♦ 4 . « * f 33*8793 



