POTASH MANURES 149 



contain 12| per cent, of potash, this is equi- 

 valent to a guarantee of 23*1 per cent, of 

 sulphate of potash. There is a tendency on 

 the part of the seller to state the percentage 

 of sulphate of potash rather than the per- 

 centage of pure potash, because the former 

 is a larger figure, and therefore more attrac- 

 tive to a certain class of buyer. Under the 

 Fertilisers and Feeding Stuffs Act, however, 

 a seller is bound to state the percentage of 

 potash, whether the percentage of the 

 sulphate is also given or not. If kainit 

 contains 12| per cent, of potash, it follows 

 that one ton will hold 280 Ib. ; and, assuming 

 a price of 2, 5s. per ton, this means that 

 the potash which it contains is costing 

 l-93d. per pound. On the Continent it is 

 the custom to sell kainit and other potash 

 manures on this basis, but in this country 

 valuation is generally made on the system 

 of units. On the basis of the figures stated 

 above, we find dividing 2, 5s. by 12| 

 that the unit-value of the potash works out 

 at just over 3s. 7d. (strictly 3s. 7d.). 



If one desires a more concentrated potassic 

 fertilizer, also containing its potash in the 

 form of sulphate, it can be obtained by 

 purchasing one or other of the manures 

 that are put on the market under the name 



