328 



BOAED OF AGRICULTURE. 



tion, and may be prepared in the same way. They are iu 

 fact only fit for an economical application as nitrogenous fer- 

 tilizers, when reduced to a fine powder. 



These substances contain in their pure condition from 11 to 

 13 per cent, of nitrogen ; yet, coming as refuse mass from 

 various industrial branches, it is well for farmers to count 

 only on about half that amount. Woollen refuse has been 

 noticed to contain even as low as from three to four per cent, 

 of nitrogen. Among the various refuse materials resulting 

 from the working of diiferent kinds of animal textures, the 

 leather refuse is probably most prominent. 



Ground refuse leather, even after steaming, is of but little 

 value for agricultural purposes ; although its percentage of 

 nitrogen may be from 5 to 9 per cent., the presence of the 

 tannic acid retards greatly its disintegration and subsequent 

 action. 



To secure the full benefit of the nitroo;en in the leather 

 refuse requires a destruction of the leather ; a result which 

 may be secured by dissolving the leather mass in boiling con- 

 centrated sulphuric acid of 50° to 60° Baume specific gravity. 

 The operation is usually carried on in leaden or cast-iron 

 vessels, and the sulphuric acid being thus charged with the 

 nitrogenous mass is subsequently turned to account for the 

 manufacture of superphosphates. 



Sulphate of Ammonia. 



Nitrogen, 

 Ammonia, 

 Sulpliui'ic acid. 



II. 



III. 



20.60 

 25.00 

 59.78 



Samples Nos. I. and III. were taken from articles sold by 

 dealers of New York City ; Sample No. II. was collected of a 

 Boston dealer. All three samples were of bluish white color, 

 and of a slightly acid reaction ; they represented in every 

 respect a good quality of their kind. Besides this light-col- 

 ored and good quality of sulphate of ammonia, there has 



