456 The Purchase of Artificial Manu es. 



4 x us. od. - - =£2 4 o 

 50 x is. 3d. - -=326 



Total - - £3 6 6 per ton, carriage paid- 

 in dissolved bones the market rate for nitrogen may be 

 put at that which prevails for nitrate of soda, while the rate 

 for the insoluble phosphate is usually the same as that in 

 bone meal. The soluble phosphate in this manure is 

 exactly the same substance, chemically, as that in superphos- 

 phate, and yet it is generally valued about is. per unit 

 higher. The only justification for this would appear to lie in 

 the fact that the insoluble phosphate, being partly reverted,, 

 should be valued somewhat higher than that in raw bone, 

 and raising the rate for the soluble phosphate makes some 

 allowance for this. 



Taking these figures, and assuming a good sample of 

 dissolved bones, we come to the following result : 



3 per cent. Nitrogen- - x 1 is. 9d.= £1 15 3 

 20 per cent. Soluble Phosphates x 2s. yd.= 2 15 o 

 16 per cent. Insol. Phosphates x is. 3d.= 1 o o 



Total - - £$ 10 0 per ton, 



carriage paid. 



Although this is about the market rate for dissolved bones,, 

 it would appear to be higher than their intrinsic merit 

 warrants. 



Kainit can usually be bought at the rate of 4s. per unit of 

 potash, so that, on an analysis of 12J per cent, of potash, the 

 price of a ton, carriage paid, would be I2jx4s.==^2 9s. 



Sulphate of Potash, containing 25 per cent, of potash 

 (corresponding to a purity of about 46 per cent.), would, at 

 the same rate, be worth 



25 x 4s. od. - - = £$ o o 



while high-class manure, containing, say, 40 per cent, of 

 potash (corresponding to a purity of about 74 per cent.),, 

 would be worth 



40 x 4s. od. - - = ^800 

 In point of fact, it is generally found that in the higher 

 grades of sulphate of potash the unit value of potash is 



