45* 



CHAPTER II. 



Atomic Constitution of Matter. 



" Omnia in mensura, et numero, et pondere disposuisti." 



Liber Sapientise, xi. 21. 



BEFORE treating of the relative quantities of 

 caloric in different bodies, and of the law by 

 which it produces the opposite forces of attraction 

 and repulsion, combination and separation, con- 

 traction and expansion ; I shall present a brief 

 outline of what is known in regard to the ulti- 

 mate constitution of ponderable matter. The 

 doctrine that everything in nature is governed by 

 measure, number, and weight, seems to have been 

 recognized by Moschus of Sidon, and other ori- 

 ental sages, long before the time of Pythagoras 

 and Democritus, who maintained that all matter 

 is composed of exceedingly small, hard, and un- 

 changeable atoms, that vary in magnitude ; so 

 arranged and combined as to produce an end- 

 less diversity of mineral, vegetable, and animal 

 bodies. 



The same theory was adopted by Bacon, Boyle, 

 Newton, and many other distinguished modern 

 philosophers, who very justly conceived that if 

 matter were infinitely divisible, all species would 

 be confounded. And it is obvious that if the 

 elements did not unite in definite proportions, 

 the laws of chemistry could not be understood, 



