138 Mr. Emmett on the [Aug. 



&c. that the same attains in the different compounds formed 

 by the union of oxygen and chlorine with metaUic bases ; that 

 in crystals of the same substance, how varied soever be the 

 external form, the figure of the nucleus is invariable ; that all 

 bodies expand by an increase, and contract by a diminution of 

 their sensible heat, following regular and peculiar laws ; that 

 under the same degree of atmospherical pressure, any given 

 hquid invariably boils at the same degree of heat, as indicated 

 by the thermometer ; that all gases are equally dilated by the 

 same increment of heat ; and that, as has been clearly proved 

 by Sir I. Newton, every particle of matter in nature attracts 

 every other particle, the force varying reciprocally in the dupli- 

 cate ratio of the distance between their centres. To suppose 

 that all chemical phenomena can admit of rigorous mathema- 

 tical investigation, would be extravagant ; we can only expect, 

 at least in the present state of chemical science, that the primary 

 laws of action can be developed ; such are cohesion, expansion, 

 construction of sohds, hquids, and aeriform fluids, radiation of 

 caloric, crystallization, and some facts relating to chemical 

 aflSnity, and the atomic theory. 



Numerous hypotheses have been advanced to explain the phe- 

 nomena of corpuscular action ; many of these appearing to be 

 liable to objections, the introductory part of these papers will 

 contain a brief examination of some of the principal systems. 



Philosophers are generally agreed that every species of pon- . 

 derable matter is composed of indefinitely minute particles, 

 atoms, or corpuscles, which are constantly under the influence 

 of two powerful antagonist forces ; viz. the centripetal, or that 

 by which, when at liberty, they tend towards each other; and the 

 centrifugal, or that repellent force which results from the opera- 

 tion of that which causes the sensation of heat, which, in the 

 permanent state of any form of matter, must be in mutual 

 equilibrio. 



That matter is composed of such solid, indestructible, immu- 

 table atoms appears from (he general phenomena of chemical 

 combination, expansion, and the existence of the same matter, 

 in the solid, liquid, and gaseous state ; this has been so fully 

 and perfectly demonstrated by many eminent philosophers, that 

 any further proof would be useless. With regard to their figure, 

 nothing can be proved ; 1 shall assume it to be spherical, since 

 this adapts them in the most simple and perfect manner to the 

 formation of every variety of crystal, as that which of all solids 

 contains the greatest quantity of matter under the least surface, 

 and the only sohd which can exert the same force at all equal 

 distances from its centre. In explaining the phenomena of 

 cohesion, it is immaterial of what figure we assume the particles 

 of matter, provided it be such as may be formed by the revolution 

 of a curve of finite curvature, and which returns into itself, upon 

 its axis, as will subsequently be demonstrated, but if the parti-. 



