FERTILIZERS. 233 



When tViose matters have been combined in the bodies of vegetables they are fitted to become 

 the food of animals ; they are not absolutely changed into any thing else ; there is a recombi- 

 nation of some bodies, and certain additions to the mineral substances which are derived from 

 the vegetable kingdom. These organic bodies are formed by the union of oxygen, carbon, 

 nitrogen and hydrogen, elements which play an important part in all organized bodies. Though 

 these elements form constituent parts of the earth's crust, yet it would seem, from' certain 

 facts, that the vegetable kingdom is the field in which they are combined and prepared, and 

 put in a proper state to become nutriment for animals; yet it is not by any means certain 

 but the combinations may take place in the interior and exterior of the earth. First, there 

 is an immense supply of carbon, from the carbonates of the earths and alkalies. The primi- 

 tive limestone, which I have described in the volume containing a description of the rocks 

 of the Second Geological District of New-York, and which was first brought to the notice 

 of geologists by myself, in the reports for that district, is a rock occupying a position simi- 

 lar to granite, and hence must exist deep in the earth. Hence it is exposed to all.;^those 

 chemical agencies which are competent to decompose the rock and set free the carbonic acid, 

 which in escaping can hardly fail to be brought to the surface. It will also form new combi- 

 nations ; it will be absorbed by water, soils, etc. Carbonic acid then may be supplied in the 

 earliest states of the earth, and as carbon constitutes, in all vegetables, a very large propor- 

 tion of their solid parts, it is essential to them ; and however much may be required for this 

 purpose, it appears from observation that the supply from the source I have named, must 

 equal the wants of a kingdom. Carbonic acid, too, is continually escaping from the earth in 

 some districts, showing clearly the probability of the position t have taken in regard to the 

 carbonates in general, and the primary limestone in particular. Of nitrogen It may be said, 

 too, that there is really no necessity for maintaining that its only supply is from organized bo- 

 dies, inasmuch as ammonia, too, is a product of volcanic action, or of the chemical reactions 

 which are constantly taking place in the interior of the earth. 



Of oxygen and hydrogen it is scarcely necessary to attempt to point out the sources of 

 supply, in any state of the earth's crust, inasmuch as oxygen forms a very large proportion of 

 the crust itself, forming with all bodies combinations from which a supply for the vegetable 

 kingdom might be derived. Water is one of the great sources of hydrogen ; it is also a con- 

 stituent of many other bodies, and hence the supply of the four organic elements, those which 

 seem to be required to constitute an organ, could have been furnished directly from the interior 

 of the earth, or from its surface, prior to the growth of a single vegetable ; and the supply 

 was great. Hence, too, it seems that the hypotheses of some chemists, in regard to the supply 

 of vegetation in its first beginning upon the earth, of these bodies, arc unnecessary : it is not 

 necessary at least, to maintain that vegetation was scanty, and confined to a few of the lower 

 tribes of plants, because fertilizers, those especially which constitute the main bulk of organs, 

 could not be obtained. Other causes were in operation, which restrained the growth of veoe- 

 tables of the highest order ; for if we may form an opinion of the character of the vegetation 

 of the early periods, it was mostly marine. Rocks of the Taconic System contain the first 

 [Agricoltural Report — Vol. in.] 30 



