‘276 HOW CROPS FEED. 
Ammonia, NrrRatrs, 2ND Orcanic NITROGEN oF various AorLs. 
5 Nitrate of || Nitrogen in |-s 
. [Ammonia.|) “potash. |lorg. combin. a 
Soils. Ibs. Ibs. Ibs |g 88 
per |per}} per |per|} per | per |S3§ 
cent. jacre/} cent jacre!|cent.| acre |RSS 
o {Liebfrauenberg, light gard. soil}0.0022| 100/|0.0175*| 875 9.3 
g J Bischwiller, light garden soil... |0.0020} 100)/0.1526 |7630 7 
¢ | Bechelbronn. wheat field clay. /0.0009} 45//0.0015 | 5 2 
& lArgentan, rich pasture......... 0.0060] 300)/0.0046 | 230 
a [Rio Madeira, sugar field, clay|0.0090| 450//0.0004 | 20 3 
2 | Rio Trombetto,forest heavy do. /0.0030} 183)|0.0001 5 9 
© | Rio Negro, prairie v. fine gand.|0.003S} 190)/0.0001 5 6 
& | Santarem, cocoa plantation.. 0.0083] 415//0.0011 | 55)/ 0. Ai 
<<} Saracca, near Amazon, loam.. |0.0042/ 210 none 0.182] 9100) 1:3.2 
| Rio Cupari, rich leaf mould... ./0.0525/2875 ue 0.685] 34250) 1:18.83 
= | Iles du Salut, French Guiana... |0.00S0] 400 |0.0643 |3215]/ 0.543) 27170) 1:11.7 
w® | Martinique, sugar ficld......... 0.0055! 275/10.0186 | 930|| 0.112] 5590! 1:8 
* The same soil whose partial analysis has just been given, but examined for 
nitrates at another time. 
It is seen that in all cases the nitrogen in the forms of 
ammonia ¢ and nitrates { is much less than that in organic 
combination, and in most cases, as in the Liebfrauenberg 
garden, the disparity is very great. 
Nature of the Nitrogenous Organic Matters. Amides. 
—AHitherto we have followed Mulder in assuming that the 
humic, ulmic, crenic, and apocrenic acids, are destitute of 
nitrogen. Certain it is, however, that natural humus is 
never destitute of nitrogen, and, as we have remarked in 
case of peat, contains this element in considerable quanti- 
ty,-often 3 per cent or more. Mulder teaches that the 
acids of humus, themselves free from nitrogen, are nat- 
urally combined to ammonia, but that this ammonia is 
with difficulty expelled from them, or is indeed impossible to 
separate completely by the action of solutions of the fixed 
alkalies. In all chemistry, beside, there is no example 
of such a deportment, and we may well doubt whcther 
the ammonia that is slowly evolved when natural humus 
is boiled with potash is thus expelled from a humate of 
ammonia. It is more accordant with general analogies to 
+ Ammonia contains 82.4 per cent of nitrogen. 
} Nitrate of potash contains 13.3 per cent of nitrogen, 
