HI8T0BY OF THE ATOMIC THEOEY. 233 



This determined him to state the ratios of these constituents 

 in numbers, and to consider the olefiant gas a compound of 

 one atom of carbon and one atom of hydrogen ; and car- 

 buretted hydrogen of one atom of carbon and two atoms of 

 hydrogen. The idea thus conceived was applied to carbonic 

 oxide, water, ammonia, &c., and numbers were given represent- 

 ing the atomic weights of oxygen, azote, &c., deduced from the 

 best analytical experiments which chemistry then possessed." 



His first atomic weights, already given,* were published in 

 1803 ; he did not publish his " New System" till 1808. He 

 says then, t " A pure elastic fluid is one, the constituent parti- 

 cles of which are all alike, or in no way distinguishable. 

 * * * These fluids are constituted of particles possessing 

 very diffuse atmospheres of heat, the capacity or bulk of the 

 atmosphere being often one or two thousand times that of the 

 particle in a liquid or solid form. Whatever, therefore, may 

 be the shape or figure of the solid atom abstractedly, when 

 surrounded by such an atom it must be globular ; but as all 

 the globules in any small given volume are subject to the 

 same pressure, they must be equal in bulk, and will, therefore, 

 be arranged in horizontal strata like a pile of shot.'* 



The chapter " On Chemical Synthesis" gives his theory. 

 He there says, " When any body exists in the elastic state, its 

 ultimate particles are separated from each other to a much 

 greater distance than in any other state ; each particle occu- 

 pies the centre of a comparatively large sphere, and supports 

 its dignity by keeping all the rest, which, by their gravity, or 

 otherwise, are disposed to encroach on it, at a respectful dis- 

 tance. When we attempt to conceive the number of particles 

 in an atmosphere, it is somewhat like attempting to conceive 

 the number of stars in the universe ; we are confounded with 

 the thought. But if we limit the subject, by taking a given 

 volume of any gas, we seem persuaded that, let the divisions 

 be ever so minute, the number of particles must be finite; just 



• Page 49. f *' A Now System of Chemical Philosophy." Part I., p. 145. 

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