60 SCIENTIFIC AGRICULTURE. 



134. The manufacture of superphosphates is per- 

 haps too difficult for the ordinary farmer, and yet 

 in some cases it can be made profitable. To any 

 one disposed to try the experiment, the following 

 directions are given, which, if strictly followed, will 

 insure a good result : 



Secure a carboy of sulphuric acid, commonly 

 known as " oil of vitriol," break up the bones as fine 

 as possible, and to one hundred pounds of bones 

 add forty pounds of acid, previously mixed with 

 twice its bulk of water, and cooled. The mixing of 

 the acid and water together produces great heat. 

 It is best to pour the acid into the water with con- 

 stant stirring. After the mass has become pasty by 

 solution of the bones, add ashes, mix thoroughly, 

 and allow the mass to dry. It can easily be re- 

 duced to a powder, and thus applied to the soil. A 

 long trough or one or more barrels may be used in 

 making the solution, or the finely broken bones may 

 be placed in a pile on a suitable floor, and sprinkled 

 from time to time with diluted acid. The acid must 

 be handled with care, as it is highly corrosive. From 

 two to three hundred pounds of this mixture should 

 be used per acre. 



135. Dr. Nichols, in his " barn-floor lecture,' 5 

 gives the following practical directions for making 

 superphosphate from charred bones, a substance 

 used by sugar-refiners for decolorizing syrups, and 

 then sold to makers of fertilizers : 



" A box four feet square and one foot deep is 



