146 TALKS ON MANURES. 



ing matters, which, on the decay of the roots, remain in the land 

 in a prepared and more readily available form, than that in which 

 they originally occur. The benefits arising to wheat, from the 

 growth of clover, may thus be due partly to this prcpaiaiion and 

 concentration of mineral food in the surface-soil. 



" The clover on the hillside field, on the whole, turned out a 

 very good crop ; and, as the plant stood the winter well, and this 

 field was left another season in clover, without being plowed up, I 

 availed myself of the opportunity of making, during the following 

 season, a number of experiments similar to those of the preceding 

 year. This time, however, I selected for examination, a square 

 yard of soil, from a spot on the brow of the hill, where the clover 

 was tiiin, and the soil itself stony at a depth of four inches; and 

 another plot of one sciuare yard at the bottom of the hill, from a 

 phice where the clover was stronger than that on the brow of the 

 hill, and the soil at a depth of six inches contained no large stones. 



SOIL NO. 1. (CLOVER THIN), ON THE BROW OF THE HILL. 



" The roots in a square 3'anl, six inches deep, when picked out 

 by hand, and cleaned as much as possible, weighed, in their natural 

 state, 2 lbs. 11 oz. ; and when dried on the top of a water-bath, for 

 the purpose of getting them brittle and fit for reduction into fine 

 powder, 1 lb. 13 oz. 31 grains. In this state they were submitted 

 as before to analysis, when they yielded in 100 parts : 



COMPOSITION OF CLOVER-ROOTS, NO. 1, (FROM BROW OF 



HILL). 



Moisture 4.34 



Organic matter* 26.53 



Mineral matter 69.13 



' 100."00 



* Containing nitrogen , 816 



Equal to ammonia 991 



" According to these data, an acre of land will yield three tons 

 12 cwts. of nearly dry clover-roots, and in this quantity there will 

 be about 66 lbs. of nitrogen. The whole of the soil from which 

 the roots have been picked out, was passed through a half-inch 

 sieve. The stones left in the sieve weighed 141 lbs. ; the soil 

 which passed through weighing 218 lbs. 



" The soil was next dried by artificial heat, when the 218 lbs. 

 became reduced to 185.487 lbs. 



•* In this partially dried state it contained : 



