36 CHEMICAL MANURES. 



To put the value of this method beyond doubt, I will report the 

 results given under three different conditions. 



At the experimental farm at Vincennes were obtained in 1864 the 

 following returns from wheat : 



Complete fertilizer 56.44 bu. 



without lime 53.33 " 



potash 40.44 " 



phosphate 34.66 " 



" " " azotic matter 18.88 " 



Without any fertilizer 15.88 " 



The conclusion is evident. At Vincennes the complete fertilizer 

 was necessary ; the azotic matter was most deficient. 



An eminent agriculturist of the department of the Somme 

 furnished me with my second example, which is upon the beet : 



Complete fertilizer 45.04 Ibs. the acre. 



without lime 41.03 



" " " potash 37.03 



phosphate 32.08 



" " " azotic matter 32. 



Without any fertilizer .22.02 



You see here, also, the earth is wanting in azotic matter, and to put 

 it under high culture we must have recourse to the complete fertilizer. 



This experiment was made at Mesnil-Saint-Nicaise, under the care 

 of M. Cavallier. 



I will borrow my third example from a culture of sugar-cane, in- 

 stituted by the Hon. M. de Zebrun, of Guadaloupe, a former delegate 

 from that colony : 



Complete fertilizer 50,666 Ibs. the acre. 



" " without lime 44,444 



potash 32,111 



phosphate 13,333 



azote 49,777 



Without any fertilizer 2,666 



If I add that sugar-cane particularly draws its azote from the air, 

 you will conclude that the soil is particularly wanting in potash and 

 phosphate of lime. 



Here are, then, two methods of knowing the richness of the land. 

 The first founded on the culture of two different plants without any 

 fertilizer, and the second on the culture of the same plant with five 

 different fertilizers. These two applications of the same principles 

 lead to the same results, and verify and complete each other. 



I need not add, that for each of these trials to have its full signifi- 

 cation the earth must not be used until the effect of each fertilizer 

 has been spent. 



You see, gentlemen, after having defined all the agents which enter 

 into the composition of plants, we have distinguished between those 

 of which nature furnishes an inexhaustible supply to vegetation, and 



