POTASH MANURES 151 



cartage, as well as the labour of distributing 

 are reduced. 



Farmers have also at their disposal a 

 manure in which the potassium is not com- 

 bined with sulphuric acid but with chlorine, 

 this manure appearing on the market under 

 the names of Chloride, or Muriate of Potash. 

 It is generally sold of a high degree of purity, 

 usually about 90 per cent., which is equivalent 

 to a guarantee of 56'85 per cent, of potash. 

 The calculation here is a little more compli- 

 cated than in the case of the sulphate. Every 

 74 '6 Ib. of chloride of potash (strictly speak- 

 ing, chloride of potassium) consists of 39-1 Ib. 

 of potassium combined chemically with 35*5 

 Ib. of chloride. A 90 per cent, sample of 

 chloride of potash, therefore, holds 47'2 per 



/39-1 x 90 _\ AT 

 cent, of potassium I *r^ =47'2J. Now, 



potassium is not potash, but it can form it 

 by uniting with oxygen ; 78'2 Ib. of potassium 

 combining with 16 Ib. of oxygen to form 

 94-2 Ib. of potash, so that 47'2 Ib. of 

 potassium will form 56*85 Ib. of potash. 

 This figure, therefore, is taken to represent 

 the potash hypothetically present in a 90 per 

 cent, sample of chloride of potash. A ton, 

 therefore, contains 1,272 Ib. of potash, and if 

 this be valued at l'93d. per pound, the price 



