1907.] MOST ECONOMICAL SOURCES OF NITROGEN. 1 57 



than it is at the present time. Without doubt during the 

 coming season ammonium sulphate can be generally used for 

 miscellaneous farm crops and the nitrogen secured from this 

 source is as cheap or cheaper than from any other source. It 

 should be remembered that ammonium sulphate cannot safely 

 be mixed with any material containing lime. Consequently it 

 must be kept from mixture with ashes ; basic slag ; but it can 

 be safely mixed with acid phosphate, muriate of potash, sul- 

 phate of potash. 



Dried blood containing 8 per cent, nitrogen can be 

 purchased for $38 per ton. This would make the cost of a 

 pound of nitrogen from dried blood 2.2^.^ cents per pound. It 

 will be seen that a pound of nitrogen costs 5 cents more when 

 purchased in the form of dried blood than when purchased in 

 the form of sulphate of ammonia. 



There is a limited quantity of fertilizer on the market 

 known as dried ground fish. This can be purchased for about 

 $38 per ton and contains 9.5 nitrogen and about 6 per cent, 

 phosphoric acid. If we were to consider this as a nitroge- 

 nous fertilizer alone, the nitrogen would cost from this source 

 20 cents per pound. But in every ton of this material we 

 would have in addition to the nitrogen 125 pounds of phos- 

 phoric acid. While this phosphoric acid is not immediately 

 available, yet it does possess some value and where immediate 

 results are not desired nor expected, there is no reason why 

 dried ground fish cannot be used economically as a fertilizer 

 the present season. 



Another material containing nitrogen is commonly known 

 as tankage. Just what this material is would be difficult to 

 state, but it is the refuse from slaughter houses and such 

 material as cannot be made into sausage and potted chicken 

 is used in making tankage. This material, containing 5.8 per 

 cent, nitrogen and from 11 to 12 per cent, phosphoric acid 

 can be purchased for $31 per ton. It is probable that the 

 phosphoric acid in a ton of this tankage is worth about $5. 

 This would leave the 116 pounds of nitrogen in the ton costing 

 $26 or about 22 cents per pound. It is evident that tankage at 

 this price is not an economical source of nitrogen. 



Of all the materials investigated and on which we have 

 secured prices the present fall, a pound of nitrogen can be 

 purchased in ammonium sulphate cheaper than from any 



