268 Tlie Origin and Relatio7is of the Carton Minerals. 



colamn hundreds of feet in height, in opposition to the force of 

 gravitation, and to tlie affinities of inorganic chemistry. 



The time comes, hoAvever, sooner or kiter, when the power 

 which has created and the life that has pervaded this wonderful 

 structure, abandon it. The affinities of inorganic chemistry 

 immediately reassert themselves ; in ordinary circumstances 

 rapidly tearing down the ephemeral fabric. 



The disintegration of organic tissue, when deserted by the 

 force which has animated and preserved it, gives rise to the 

 phenomena which form the theme of this paper. 



Most animal tissue decomposes with great rapidity, and plant- 

 tissue, when not protected, soon decays. This decay is essen- 

 tially oxidation, since its final result is the restoration to the 

 atmosphere of carbonic acid, wliich is broken up in plant-growth 

 by the appropriation of its carbon. Hence it is a kind of com- 

 bustion, although this term is more generally applied to very 

 rapid oxidation with the evolution of sensible light and heat. 

 But whether the process gots on rapidly or slowly, the same 

 force is evolved that is absorbed in the growth of plant-tissue ; 

 and by accelerating and guiding its evolution, we are able to 

 utilize this force in the production at will of heat, light, and 

 their correlatives, chemical affinity, motive power, electricity 

 and magnetism. The decomposition of plants may, however, 

 be more or less retarded, and it then takes the form of a de- 

 structive distillation; the constituents reacting upon each other, 

 and forming temporaiy combinations, ])art of Avhich are evolved, 

 and part remain behind. Water is the great extinguisher of 

 this as of the more rapid oxidation that we call combustion; 

 and the decomposition of plant-tissue under water is extremely 

 slow, from the partial exclusion of oxygen. Buried under thick 

 and nearly impervious masses of clay, where the exclusion of 

 oxygen is still more nearly complete, the decomposition is so far 

 retarded that plant-tissue, which is destroyed by combustion 

 almost instantaneously, and if exposed to "the elements," — 

 moisture with a free access of oxygen, — decays in a year or two, 

 may be but partially consumed when millions of years have 

 passed. The final result is, hoAvever, inevitable, and always the 

 same, viz., the oxidation and escape of the organic matter, and 

 the concentration of the inorganic matter woven into its com- 



