38 CHEMICAL MANURES. 



But after what I have told you of the origin of these three bodies 

 you will not be surprised if I tell you that their presence in the 

 manure does not add to its good effects. The same observation with 

 regard to the chlorate of sodium, of aluminum, of magnesia, of soda, 

 of silica, of the oxide of iron, etc., which manure contains, and which 

 we have excluded from the complete fertilizer, because poor land is 

 always superabundantly provided with them. 



Thus, then, the first result is that manure, the incontestable symbol 

 of fertility, contains the four bodies which, according to us, are the 

 regulators, par excellence, of production, and the only ones with which 

 agricultural industry need occupy itself. I repeat, this is an incon- 

 testable justification of our previous studies ; but that this justification 

 may be complete and without appeal to the identity of composition, 

 must be added that of effect. In this respect practice again confirms 

 our teachings.' The returns from our complete fertilizer always ex- 

 ceed those obtained from manure. 



This conclusion is of more value as it is the result from facts bor- 

 rowed from a large culture. I owe them to agriculturists who, like 

 you, are seeking truth, and who, at my request, willingly instituted 

 several comparative experiments between the chemical fertilizer and 

 the manure of the farm. 



In all these experiments the advantage rests with the chemical 

 fertilizers. The first result I will show you was obtained by M. de 

 Peyrat, sub-director on the school-farm of Beyrie, in Landes. 



On a land of ordinary quality three cultures of beet were instituted 

 the first without any fertilizer, the second with the complete 

 manure, and the third with 71,136 pounds of manure. 



Roots the acre. 



On the land without manure the return was 7,264.06 



With 71,136 pounds of manure it reached 43,844.07 



With the chemical fertilizer it rose to 47,111.24 



The chemical manure was used in the quantity of 1511 pounds, 

 which showed itself superior to a manuring of 71,136 pounds of barn- 

 yard manure. 



With M. le ,Marquis de Virien, in the Isere, the same result : 



Roots the acre. 



From 44,444.04 pounds of barnyard manure the yield 



was 41,600 Ibs. 



From 1733 pounds of the complete fertilizer was ob- 

 tained 44,444.04" 



With M. Leroy, at Varennes (Oise), from 1243 pounds 



of chemical fertilizer, the return was 55,440 " 



From 44,444.04 pounds of barnyard manure, with the 

 Addition of 133.03 pounds of guano, the return only 

 rose to 35,568 " 



At Guadaloupe, on some of the worst land of the colony, barnyard 

 manure produced 28,418.56 pounds of cane the acre. 



The chcimical fertilizer 51,552.32 Ibs. 



And the hind without any fertilizer 2,666.24 " 



