266 



EARTHY PHOSPHATES. 



The field at Kotitz got 50 per cent, more bone-dust 

 than the Ciinnersdorf field ; yet its produce of all the 

 crops was lower than that of the latter. The field at 

 Oberbobritzsch got, in 1851, twice the quantity of 

 manure that was applied to the Ciinnersdorf field ; the 

 result was, in the first year, an increase of corn of 250 

 per cent., and of straw of 66 per cent, more on the for- 

 mer than on the latter. In the third year, however, 

 the increase of produce of oats, both in grain and straw, 

 was considerably larger at Cunnersdorf than at Ober- 

 bobritzsch. 



The most curious part of the results is the great 

 difference in the increase of the produce of clover on 

 the several fields ; from the field at Oberbobritzsch 

 nearly six times as much clover was obtained as from 

 that at Kotitz, although the former had received only 

 one-fourth more bone-dust than the latter. 



A glance at the table shows that in the experiments 

 at Cunnersdorf, Kotitz, and Oberbobritzsch, the quan- 

 tities of bone-dust severally applied as manure were as 

 1 : 1J : 2. A 'comparison of the increase of produce 

 obtained by bone-earth, just as in the case of guano 

 and farm-yard manure, again demonstrates that there 

 is no connection or relation of dependence between the 

 amount of manure and the increase of the crops. 



100 Ibs. lone-dust gave increase of produce 



