FERTILIZERS. 99 



calculating the proportions of crude materials to use in 

 making up a ton of fertilizer by either of these formulas, it 

 was assumed that 



Sulphate of ammonia contains 20 per cent of nitrogen. 



Nitrate of soda contains 16 " " " 



Blood and ammonite contain 12 " " " " 

 Bone-black superphosphate 



contains 16 " " " available phosphoric acid. 

 Acid phosphate from South 



Carolina rock contains 12 " " " " " 



Muriate of potash contains 50 " " " potash. 



Kainite contains 12 " " " " 



No difficulty will be experienced, says the professor, in 

 securing supplies of these guaranteed to contain the above 

 percentages of plant-food. 



CLASS No. 1. This is a small class, containing three 

 brands, and includes all of the fertilizers in which the guar- 

 anteed nitrogen does not exceed one per cent. 



CLASS No. 2. This is a large class, containing twenty- 

 four different fertilizers, of which sixteen are intended for 

 general use, and eight are specially designed for fruit, 

 tobacco, potatoes, lawn-dressing, hops, and buckwheat. 



CLASS No. 3. This class includes eighteen different 

 fertilizers, of which eleven are for general use, and seven 

 are specially designed for sorghum, potatoes, etc. 



CLASS No. 4. This class includes twenty-one different 

 fertilizers, of which five are for general use, and sixteen 

 are specially designed for grain, tobacco, potatoes, and 

 vegetables in general. 



CLASS No. 5. This contains six fertilizers, of which 

 five are for special crops, tobacco, lawn-dressing, grain, 

 and vegetables. 



The value of the plant-food in an unmixed condition, 

 given in each formula, was calculated by using the manu- 

 facturers' average retail prices for 1884. 



