150 AGRICULTURE 



of Sulphate of Potash. One of these is 

 generally guaranteed 50 per cent, pure, which, 

 on the basis of the figures already given, 

 is equivalent to a guarantee of 27'04 per cent, 

 of potash. A ton, therefore, holds 606 Ib. 

 of potash, and if this be valued at l'93d. per 

 pound, it works out at a price per ton of 

 4, 17s. 6d. Or we can multiply 27-04 by the 

 price per unit (3s. 7d.), and, of course, we 

 arrive at the same result. A still more 

 concentrated form of sulphate of potash, 

 guaranteed 80 per cent, pure (=43-2 per cent, 

 potash), can be obtained, and the price per 

 ton may be worked out in a similar manner. 

 Which of these three manures to employ 

 will depend partly on considerations of 

 carriage, and partly on whether one wants 

 to apply considerable quantities of common 

 salt to the crop or not. If this be desired, 

 then the preference would be given to kainit. 

 The mangold crop is one which, in many 

 cases, is benefited by dressings of common 

 salt; and certainly in the case of this crop, 

 other things being equal, the preference 

 would be given to kainit. On the other 

 hand, if no special value is attached to salt, 

 the farmer would naturally prefer to use a 

 more contentrated manure than kainit, be- 

 cause, by so doing, costs of carriage and 



