220 BOARD OF AGRICULTURE, 



should be wanting in gratitude if we did not appi'eciate this kind- 

 ness on the part of the citizens here, and you may be sure that I 

 express the feelings of those students when I tender to you their 

 sincere thanks for this kindness and liberality. 



While Mr. Lebroke was speaking, one thought occurred to me, 

 which perhaps it may be well to bring out, in addition to what he 

 said. I like very much the doctrine which he advanced in regard 

 to the necessity of returning to the soil that which has been taken 

 from it. Let us carry the idea a little further, and see if he does 

 it. Undoubtedly, by his process, he carries back nine-tenths of 

 the elements that have been taken up in the growth of the plant ; 

 but he will remember that while he is rearing stock on his farm, 

 while his cows, oxen and horses are feeding on his pastures, a 

 certain amount of the material of which plants are composed is 

 being appropriated in such a manner that it cannot be returned in 

 the fertilizers of which he has spoken, which he has safely secured 

 in his barn-cellar. His animals grow, and in the growth of the 

 bones, there is an appropriation of chemical elements, which, in 

 returning the manures, he does not carry back to the soil. 



Now, how are farms to be kept up, where such is the case ? 

 One class of the young men in the college has been pursuing the 

 subject of agriculture to a certain extent. They took up, some 

 time ago, a little text-book entitled, "Elements of Agriculture," 

 and without answering the question m3^self, I propose — although 

 it may be at some hazard — to call up some of these young men, 

 to tell us in what way they will return to the soil what brother 

 Lebroke fails to return. 



Mr. Weston, what are those chemical constituents which are 

 taken up in the growth of bones which are not fully returned in 

 the manures and urine from the barn-cellars ? 



Mr. Weston. Chiefly phosphate of lime. 



Prof Fkrnai-d. Then what, in addition to the manure of the 

 barn cellar, should be given to the soils in order to maintain their 

 strength for producing plant life ? 



Mr. Weston. The bones of the animals, or an equivalent in 

 some other substance containing pliosphate of lime. 



Prof. Fernald. How may this be best obtained ? 



Mr. Weston. In the form of superphosphate, or of ground 

 bones. 



Prof. Fernald. Suppose the bones are applied to the soil with- 

 out being ground ; will they avail anything as plant food ? 



