866 



INORGANIC ELEMENTS OF MANURES .-. ND CROPS. 



main difficulty, and the more important loss. To quote one of the 

 instances, that of wheat, where the loss or deficiency is as high as 

 24 per cent. I may say that a direct inquiry after charcoal brought 

 it out equal to 2, by which the actual deficiency is reduced to 0.4. 

 I have not, however, introduced any correction for carbon, but pre- 

 sent the reader with the results as they actually presented them- 

 selves to me. Among the number of the products of the analyses, 

 alumina figures beside the oxide of iron. Alumina is an earth which 

 I have always met with in minimum quantity in the ashes of plants, 

 and is perhaps accidental ; it may proceed from the earth which ad- 

 heres to all herbaceous plants, and from which it is so difficult to 

 free them completely. 



COMPOSITION OF THE ASHES PROCEEDING FROM THE PLANTS GROWN 

 AT BECHELBRONN. 



If these analytical results be now applied to the produce of an 

 acre of ground, we should have the precise quantities of minera. 

 substances abstracted from the soil by each of the several crops tha 

 enter into the rotation. Here they are in a table : 



MINERAL SUBSTANCES TAKEN UP FROM THE SOIL BY THE VARIOUS 

 CROPS GROWN AT BECHELBRONN UPON ONE ACRE, 



