THEORIES OF THE OPERATION OF THE SOIL. 395 



an elaborate chemical analysis.&quot; This is certainly a great con 

 fession for an eminent chemist to make. 



To exemplify the different results to which the most scientific 

 men arrive in these cases, I will refer both to Boussingault and 

 Von Thaer in respect to a simple point, the presence of the car 

 bonate of lime in the soil as essential to the growth of a crop of 

 wheat, on which subject the public mind has been so long, so 

 generally, and so confidently made up. 



Von Thaer says,* &quot; The richest argillaceous soil that I ever 

 analyzed, the fertility of which was regarded as of the very richest 

 quality, was taken from the right bank of the Elbe, some few 

 miles from its mouth ; it contained eleven and a half parts in a 

 hundred of humus, four and a half of lime, a great quantity of 

 clay, a little coarse silica, and a considerable portion of very fine 

 silica, which could only be separated from it by ebullition. It 

 certainly possessed a great degree of cohesion, but, when moder 

 ately moistened, it was not very tenacious. It was made to bear 

 the richest crops, as cabbages, wheat, autumnal corn, beans, &c. ; 

 but every sixth year it was necessary to manure it thoroughly, 

 and to give it a fallow.&quot; 



On the preceding page, he says, &quot; The richest land I ever ana 

 lyzed, and which was taken from the marshes of the Oder, 

 contained 192- parts in 100 of humus, 70 of clay, a little fine 

 sand, and an almost imperceptible quantity of lime ; but the situ 

 ation of this land was too low, and it was too damp, to admit of a 

 correct estimate being formed of its fertility.&quot; 



Boussingault says,f &quot; I may remark generally, that, from the 

 whole of the analyses of good wheat lands which have hitherto 

 been made, it appears that carbonate of lime enters in consid 

 erable quantity into their composition ; and theory, in harmony 

 with practice, tends to show that it is advantageous to have this 

 earthy salt as a constituent in the manures which are put upon 

 soils that contain little or no lime.&quot; 



On the next page, J he says, &quot; M. Berthier s analysis is still 

 far from proving that the presence of lime in a soil is indispen 

 sable, inasmuch as beautiful wheat crops are grown in the neigh 

 borhood of Lisle without lime. In proof of this fact, I shall 

 here cite the analysis of one of the most fertile soils in the world, 



* Vol. i. pp. 355, 354. f Rural Economy, p. 294. \ p. 295. 



