248 



The following analyses were made by Thos. Way and G. H. Ogston 

 and will give an idea of the drain upon land which is used for cereals, 

 hay, &c. Pounds per acre : 



Barley 

 Hay . 

 Flax . 

 Hops 

 Corn . 



KCl 

 6.3 



2.2 



15.0 



none. 



It must be remembered that there is added to the roots of a tree an 

 amount of wood equal to that added to the top, the composition of which 

 as compared with the top may be seen in analyses Xos. 9 and 10, but since 

 the wood of the root is never taken from the ground the mineral constit- 

 uents which are a part of its composition can never be said to be taken 

 from the field, yet in a growing tree the fact must be remembered and a 

 rate of exhaustion allowed for the roots equal to that of the branches. 



There is also taken up by the leaves an amount of mineral constituents, 

 the per cent, of which is shown by the following table taken from Dr. 

 Wolff's ash analysis. 



LEAVES OF 



Much of this material, however, returns to the land and need not.be con- 

 sidered as very important in the calculations. 



The only part of the mineral constituents absorbed by the tree that are 

 carried away from the field is that portion contained in the fruit. The 

 amount of fruit grown on difterent trees varies within such wide limits 

 and its mineral constituents vary so much with the quality of the fruit 

 that onlj"^ very general conclusions can be given. 



The results below, taken from Dr. Wolff's ash analysis, show the com- 

 position of the ash of some of the common fruits : 



