The Evolution of the Sciences 



Thus classical chemistry consists almost 

 entirely of chemical notation; when it has 

 written the equation of a reaction it is satisfied 

 that nothing remains to be told, and the succes- 

 sion of its monographs are in their turn con- 

 densed into structural formulae. All its efforts 

 are directed to the establishment of these 

 formulae, they are its supreme object; it is, in 

 fact, impossible to conceive a more elastic and 

 expressive manner of representing a body. 

 Take the formula of alcohol: 



H H 



I I 

 H CC H 



I I 

 H O H 



It discloses the qualitative and quantitative 

 composition of this body and its vapour density, 

 it shows its essential properties and the action 

 exercised by it on most other bodies, and all 

 this without the intervention of a single 

 hypothesis; if we further admit the atomic 

 conception of matter our formula presents an 

 image of the molecular structure built up of 



the atoms of the elements; in fact, so 



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