40 MODERN HIGH FARMING. 



Taking the active principles to be in the proportion of 27 pounds 

 of nitrogen and 6 pounds of phosphoric acid per ton, we can easily 

 arrive at the annual total value by the following simple calculation : 



27 -f 20,000,000= 270,000 tons nitrogen, at $50 per ton, $13,500,000 

 6 + 20,000,000= 60,000 " phosphoric acid, $30 " 1,800,000 



Net total value, $15,300,000 



It is a standing reproach to chemical science that we have not 

 been able to devise a means of practically turning these vast agricul- 

 tural necessities to account, and that because of our inability to con- 

 veniently store and render them inoffensive, our legislators are com- 

 pelled to send them through the sewers into the sea. 



All the attempts hitherto made to recover these substances from 

 the sewage by means of precipitation have ended in failure, from the 

 fact that chemistry has not yet discovered a method of effecting this 

 precipitation, owing to the extreme solubility and volatility of the 

 efficient constituents. 



If these elements of fertilization are ever to be turned to good 

 account in the proper channels for their employment, they must be 

 kept out of the sewers, where they do immense harm by contamina- 

 ting our drinking water and propagating diphtheria, and be sub- 

 mitted to some practical process of rapid desiccation. 



The system by which these materials are turned to account in 

 some parts of Europe, consists in allowing them to deposit in 

 tanks, built for the purpose. In due course the supernatent liquid is 

 decanted off and used for the manufacture of sulphate of ammonia ; 

 while the solid portion is dried up by the addition of slaked lime, 

 and sold in bags under the familiar name of poudrette. 



A good sample of this manure, lately submitted to us for 

 analysis, was found to contain forty-eight per cent, of organic 

 matter, two and one-Tourth per cent, of nitrogen, six per cent, of 

 phosphoric acid and ten per cent of lime ; and would doubtless be 

 productive of very excellent results in the field. 



Wherever such operations are practicable, we strongly recom- 

 mend all farmers to build small tanks in various portions of their 



