On Agricultural Chemistry. 



used, which gave 20^ bushels, or rather more than 2 bushels 

 beyond the produce of the unmanured plot ; but as the manure 

 contained, besides the minerals peculiar to it, some nitrogenous 

 compounds, giving off a very perceptible odour of ammonia, some, 

 at least, of the increase would be due to that substance. On 

 plot 65, however, the further addition of 1 cwt. each of sulphate 

 and muriate of ammonia to this so-called " Mineral Manure," 

 gives a produce of 29^ bushels. In other words, the addition of 

 ammoniacal salt to Liebig's mineral manure has increased the 

 produce by very nearly 9 bushels per acre beyond that of the 

 mineral manure alone, whilst the increase obtained over the 

 unmanured plot, by 14 tons of farm-yard manure, was only 

 9i bushels ! 



If, then, the " mechanical form and chemical qualities " of 

 the so-called ''Mineral Manure" were at fault, the sulphate of 

 ammonia has, at least, compensated for the defect ; and even 

 supposing a mineral manure, founded on a knowledge of the 

 composition of the ashes of the plant, be still the great deside- 

 ratum, the farmer may rest contented, meanwhile, that he has in 

 ammonia, supplied to him by Peruvian guano, by ammoniacal 

 salts, and by other sources, so good a substitute. 



In Table IV. are one or two of the results of the harvest of 

 1847, which bear upon our question. 



Table IV. 



Harvest 1847. Selected Results. (See fourth section of diagram I., 

 opposite p. 14.) 



Description and Quantities of the Manures per Acre. 



Dressed Com 

 per Acre, 

 in Bushels 

 and Pecks. 



Total 

 Corn 

 per Acre, 

 in lbs. 



Straw 

 per Acre, 

 in lbs. 





bush. 



pecks. 



lbs. 



lbs. 



Section 1. 













16 





1123 



1902 



,5 2. 14 tons of farm-yard manure . . 



29 





1981 



3628 



Section 2. 











, , 9a\ 1 ton of Rice ..... 



Q 2 J Sulphate of ammonia 150 lbs. \ 

 " ^ 't Muriate of ammonia 150 lbs. J * 



22 



3 







26 



2 













( Sulphate of ammonia 150 lbs. 1 

 " * t Muriate of ammonia 150 lbs. j 



26 



0 











The produce of the continuously unmanured plot is now seen 

 to be almost 17 bushels of dressed corn, and that of the plot with 

 farm-yard manure nearly 30 bushels. 



Plots 9a and 9Z>, the former of which had in the previous sea- 

 son 4 cwts. of rape-cake, and the latter 4 cvvts. of rape-cake and 



