or Black Earth of Russia. 



133 



Whilst the analyses of these able chemists afford us nearly the 

 same results as to the proportions of solid materials, we learn 

 from M. Pay en that the peculiar gaseous contents of the black 

 earth may be the principal cause of its fertility. It would seem, 

 indeed, that without a close attention to the proportion, not only 

 of the soluble and insoluble constituents of soils, but also to their 

 gaseous contents and their mechanical aggregation, it must be 

 very difficult to estimate their fertilizing powers. Thus, in looking 

 through the various British soils analyzed by Mr. R. Phillips, I 

 find that a red, brick-coloured earth, already alluded to, from a 

 property of Lord Calthorpe, (as dissimilar as possible in aspect 

 and aggregation from the Tchornoi Zem of Russia, and differing 

 also from it, I will venture to say, in produce,) has almost to 

 minute quantities the same relative proportions of sand, clay, iron, 

 and vegetable matter ; though the Russian earth is black, perme- 

 able, and easily managed, and the English earth is red and tena- 

 cious. Again, we see by the comparisons of M. Payen with 

 what very different soils in France he compares the Tchornoi 

 Zem of Russia. 



4. When we speculate on the probable origin of the Tchornoi 

 Zem, the first impression might be that which the Baron A. 

 von Meyendorf adopted in a letter to M. Elie de Beaumont, 

 and which is indeed the prevalent opinion in Russia, viz. that it 

 is the humus arising from decayed forests or vegetables. But I 

 am obliged to dissent from this opinion, seeing the uniform nature 

 of the soil and its distribution at all levels without reference to 

 the existing drainage ; and also from the fact, that in no part of the 

 empire did my associates or myself ever perceive a trace of trees, 

 roots, or vegetable fibre in the black mass. It is in vain to say 



Mat. soluble dans ac. 

 chlorbyd, boitillaut = 



Alumine .... 

 Ox. de fer . 



Sulfte. chx. = 0-036 1 

 = cbaux . . .j 

 Magnesie .... 

 Chlorures alcals. . 



Mat. insoluble ac. 

 chlorbyd. bouillaut = 



Sillce . 



Alumine 



Chaux 



Magnesie 



1-368 Per 100. 



1-232 90-24 

 0-110 8-03 



traces. 

 0-008 I 0-90 



DOSAGE DE L AZOTE. 



Donnees. 

 Mat. employee = 4-110 

 Pression = 



Temperat. = 



76-94 

 19<: c^^ 

 9<^« 9 



Mis vide 

 Perte 



9- 190) eau per cent. 

 0-29Uf = 4-81 



A incinerer = 1 - 724 1 cendre per cent. 

 Cendres(rcuges)= 1-609J =93-09 



Restcltais. 



Mat. normale employee = '4*140 



„ seche = 3-940 



,, organique pure = 0-279 



Vol. reel, de Fazote = 9c''498 



Poids „ = 6i^ e 861 



azote { Mat. normale = 1 • 66 



„ seche = 1-74 



„ pure = 24-99 



pour 

 1000 



