294: AMMONIA AND NITKIC ACID. 



If the smallest doubt could exist on this question, 

 it is completely removed by the investigations of Schmid 

 and Pierre (' Compt. rend.' t. xlix. pp. 711-715). 



Schmid examined (see Peters. 4 Acad. Bull.' viii. 

 161) several specimens of Kussian black-earth (tscherno- 

 sem) from the Government of Orel, and among them 

 three from the same field, marked by him as ' virgin 

 soil,' of which we may assume that it had never been 

 subject to agricultural operations ; the amount of nitro- 

 gen in this soil amounted to 



Amount of nitrogen in the tscherno-sem. 



Under the turf 0*99 per qent. nitrogen 



4 werschoks (= 7 inches) deeper. . 0-45 " " 



Above the subsoil 0'33 " 



If we assume a cubic decimetre ( 61 cubic in.) of 

 this earth to weigh 1100 grammes ( 2'4 Ibs.), then, 

 calculating for the area of a hectare ( 2-J acres), the 

 ground would contain 



kilo. cwt. 

 1 decimetre (= 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 neighbourhood of Caen, 

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

 nitrogen distributed, in the following manner, through 

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



centimetres, inches. kilogr. cwt. 



In the first layer of 25 =10 deep, the soil contained 8360 = 164 



" second " 2550 = 1020 " 4959 = 97 



" third " 5075 = 2030 " 3479 = 68 



" fourth " 75100 = 3040 " " 2816= 55 



19614=384 



Thus, 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. 



