NITROGEN IX THE DIFFERENT LAYERS OF SOILS, ail 



to agTicultural operations ; the aiiiouut of nitrogen in this 

 soil amounted to — 



Amount of nitrogen in the tscJicrno-scm. 



Under the turf 099 per cent, nitrogen 



4 -werschoks ( = 7 inches) deeper . . 0-4o „ „ 



Above the subsoil 0-33 „ ,, 



If we assume a cubic decimetre ( = G1 cubic in.) of this 

 earth to weigh 1100 grammes (=2*4 lbs.), then, calculating 

 for the area of a hectare (=2^ acres), the ground would 

 contain — 



kilo. cvrt. 

 1 dceimttro ( = 4 inches) deep . . . 10890 = 213 nitrogen 

 1 ,, „ deeper . . 4950= 97 „ 



1 „ „ „ . . . 3630= 71 



30 centimetres ( = 11-7 inches) deep . . 19470 = 381 „ 



In examining a soil in the neigiibourhood of Caen, 

 Pierre found in it 19620 kilogrammes (=385 cwt.) of 

 nitrogen distributed, in the follo^ving manner, through 

 a hectare to the depth of one metre (=3-3 feet). 



kilogr. cwt. 

 deep, the soil contained 8360 = 164 

 4959= 97 

 3479= 68 

 2816= 55 



19614 = 384 



Tlius, according to both investigations, the uppermost 

 layers, or the proper arable soil (about 10 inches deep), 

 were the richest in nitrogen, while in the lower layers the 

 amount decreased. 



Such a condition undeniably proves the origin of 

 nitrogen in the arable soil. 



If the upper layers, which are constantly deprived of 

 nitrogen by cultivation, contain more of this element than 

 the lower, it necessarily foUows that tlie nitrogen must 

 have come from witliout. The analysis of tJie most 



