L. V. BELL'S ADDRESS. 593 



Prof. Shepard, one of the chemical teachers at the south, 

 analyzed carefully the yam, and found that there were some 

 fourteen ingredients in it. Cow dung had been so often and 

 carefully analyzed by my friend and relative, Dr. Dana, of 

 Lowell, in his finally successful endeavors to supplant the 

 necessity of keeping a large stable of cows for the use of their 

 manure in calico printing, (by ascertaining the precise drug 

 wanted, and obtaining it from cheaper sources,) that nothing 

 could be better known. These analyses demonstrated that 

 cow manure had only five of the fourteen elements of the yam, 

 and that in so insignificant a quantity that the whole amounted 

 to only from one-half to one per cent. 



The urine of the animal was next passed under analysis, 

 which, of course, under the cow-penning system was lost in the 

 subjacent soil, but which had been wasted in their methods of 

 manure saving. It was found to contain the identical four- 

 teen elements of the yam, and some others which were not 

 essential. Could any demonstration be more conclusive ? 



But it is not only in these experiments of the scientific man, 

 or the minor fields of farming, that the truth of our doctrine is 

 made manifest. 



The history of the application of guano and that of agricul- 

 tural chemistry run together. In the worn out and exhausted 

 fields of Europe, under thousands of years of grain cultivation, 

 any person who saw their dark and rich mould turned up to 

 the light, could be in no doubt that there was neither exhaus- 

 tion nor deficiency in the great organic essentials. Chemistry 

 told him that it was the two or three most limited articles, so 

 far as quantities are regarded, which had been carried off in 

 crop after crop. Chemistry told him that guano had these 

 things ready for use, and on the strength of this theory, verified 

 by an immensity of testimony, guano has already become one 

 of the great articles of the world's commerce, for which fleets 

 are fitted out and wars threatened. Probably over two hun- 

 dred thousand tons of this article will be carried into Eno-land 

 the present year, at a cost of over ten millions of dollars. 

 Those of my audience who recall the recent correspondence 

 between Capt. Jewett and the Secretary of State, touching the 

 great operations now on foot for transporting this article from 

 the Lobos Islands on the coast of Peru, will understand the 

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