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CHAPTER, XL 



CHEMICAL FORCES. 



Nature's Chemistry Changes produced by Chemical Combina- 

 tionAtomic Constitution of Bodies Laws of Combination 

 Combining Equivalents Elective Affinity Chemical 

 Decomposition Compound Character of Chemical Plie- 

 nomena Catalysis or action of Presence Transformation 

 of Organic Bodies Organic Chemistry Constancy of 

 Combining Proportions The Law of Volumes, the Law of 

 Substitutions, Isomeric States, &c. 



ALL things on the earth are the result of chemical com- 

 bination. The operations by which the commingling of 

 molecules and the interchange of atoms take place, we 

 can imitate in our laboratories ; but in nature they 

 proceed by slow degrees, and, in general, in our hands 

 they are distinguished by suddenness of action. In 

 nature chemical power is distributed over a long period 

 of time, and the process of change is scarcely to be 

 observed. By art we concentrate chemical force, and 

 expend it in producing a change which occupies but a 

 few hours at most. Many of the more striking pheno- 

 mena of nature are still mysterious to us, and principally 

 because we do not, or cannot, take the element time 

 into calculation. The geologist is compelled to do this 

 to explain the progress of the formation of the crust of 

 the earth, but the chemist rarely regards the effects of 

 time in any of his operations. The chemical change 

 which within the fissure of the rock is slowly and 

 silently at work, displacing one element or molecule, 



