needed for plant food? It will be remembered that 

 nitrogen is a gas, and phosphoric acid and potash 

 respectively strong acid and alkali, and that they 

 can only be useful in combined forms. If medium 

 grade materials were used in the manufacture of the 

 average fertilizer, as stated above, it might be made 

 up about as follows : 



440 pounds of organic matter (blood, tankage, etc.) 

 850 pounds of ground S. C. rock and sulphuric acid, 

 llo pounds of muriate of potash. 



1400 Ibs. 



This would leave 600 pounds, or 30 per cent, of 

 the gross weight in every ton for moisture, dirt and 

 useless material on which freight, mixing and bagging 

 expenses, storage, etc., must be paid by the consumer. 



A complete analysis of the above 1400 pounds 

 would probably resemble the following : 



Water 16.0 (Combined with organic 



matter and sulphuric acid ) 



Nitrogen 2.2 



Phosphoric acid 10.6 



Potash 2.9 



Volatile and organic 33.0 (Combined with nitrogen) 



Gypsum 16.0 (Formed by action of 



sulphuric acid on rock.) 



Lime 7.1 (Leftcombined with phos- 

 phoric acid.) 



Sand 4.0 (Impurity phosp. rock.) 



Chlorine and Salts.. 3.0 (Combined with potash.) 

 Miscellaneous... 5.2 



