Manures and Fertilizers. 37 



The phosphate ingredient will probably be derived from 

 superphosphates, costing 2 2s. per ton, and containing 30 per 

 cent, total phosphates, of which 26 per cent, is soluble and 4 

 per cent, insoluble. The unit-value is ascertained by dividing 

 the price, 2 2s., by 26, the percentage of soluble phosphates ; 

 the result is Is. 7d., which is the unit- value. The insoluble 

 phosphates in superphosphates are regarded as valueless. 



The potash ingredient will probably be derived from sulphate 

 of potash, which contains 50 per cent, pure potash and costs 

 9 10s. per ton. By dividing 9 10s. by 50 we arrive at 3s. 9d. 

 as the unit-value of potash derived from sulphate of potash. 



We can now form a clear judgment of the fair price of the 

 mixed fertilizer, thus: 



Nitrogen, 5 per cent., at 12s. for each unit 



5 times 12s. = 3 



Soluble Phosphates, 17 per cent., at Is. 7d. 



for each unit 17 times Is. 7d. = 1 611 



Insoluble Phosphates (valueless) ... ... ... 



Pure Potash, 6 per cent., at 3s. 9d. for each 



unit 6 times 3s. 9d. - 126 



Add 25 per cent, to cover mixing, bags, waste, 



carriage and profit 1 7 7 



6 17 



It will thus be seen that, at present market prices, a manure 

 of the fertilizing value of that under examination, when 

 compounded of mineral ingredients, ought not to cost more 

 than 6 17s. per ton, carriage paid to the purchaser's nearest 

 railway station. When the fertilizer is compounded of organic 

 ingredients the unit-values will average about 25 per cent, 

 higher. 



In judging the money-values of manures it must be con- 

 stantly borne in mind that the unit-values will vary as the 

 market prices of the materials fluctuate. They do not include 

 the cost of carriage, and they are based on the price of mate- 

 rials when bought in quantity. 



