XVI. 



THEORY OF CHEMICAL CHANGES AND 

 EQUIVALENT VOLUMES. 



(1853.) 



The following paper was published under the title of Considerations on the Theory 

 of Chemical Changes, etc., in the American Journal of Science for March, 1853. It 

 soon after appeared in the London, Edinburgh, and Dublin Philosophical Magazine (4), 

 V. 526, and was translated into German and appeared in the Chemisches Centralblatt of 

 Leipsic in the same year (page 849). In the papers which follow, on The Composition 

 and Equivalent Volume of Mineral Species, on Solution and the Chemical Process, on 

 The Objects and Method of Mineralogy, as well as in that on The Theory of Types in 

 Chemistry, I have attempted to develop some of the notions contained in this first 

 essay, which, I still think, must form the basis of a rational theory of chemistry 

 and a true mineralogical classification. 



IN the proposed inquiry we commence by distinguishing be- 

 tween the phenomena which belong to the domain of physics 

 and those which make up the chemical history of matter. "We 

 conceive of matter as influenced by two forces, one of which 

 produces condensation, attraction, and unity, and the other ex- 

 pansion, repulsion, and plurality. Weight, as the result of 

 attraction, is a universal property of matter. Besides this, we 

 have its various conditions of consistence, shape, and volume, 

 with the relation of the latter to weight, constituting specific 

 gravity, and the relations of heat, light, electricity, and magnet- 

 ism. A description of these qualities and relations consti- 

 tutes the physical history of matter, and the group of characters 

 which serve to distinguish one species from another may be 

 designated the apparent or specific form of a species, as distin- 

 guished from its essential form. 



The forces above mentioned modify physically the specific 

 characters of matter, but they have besides important relations 



