310 AGRICULTURAL EXPERIMENT STATION. [Jan. 



The resulting mixture, when in fairly dry condition, would 

 weigh approximately 5,000 pounds, shrinking about 18 to 

 20 per cent. It would have aj)proximately the following 

 composition : — 



Per Cent. 



Moisture, 18.00 



Available pliosi^horic acid, 8.50 



Insoluble phosphoric acid, 2.00 



Total phosphoric acid, 10.50 



Total nitrogen, . . .90 



Two thousand pounds of sulphuric acid will not take up 

 more than 600 pounds of leather and render the leather 70 

 per cent, digestible. If more is added, part of the latter, 

 whether roasted or raw, will not ])e thoroughly acted upon 

 by the acid. With GOO pounds of leather a thick paste 

 results, which must be dihitcd somewhat with water in order 

 to allow the sulphuric acid to act freely upon the floats. If 

 bone ash should be used as a dryer, in place of ground phos- 

 phate rock, a higher percentage of available phosphoric acid 

 and of nitrogen would result, as experiments I. and II. 

 indicate. 



Before submitting the leather to the action of the sulphuric 

 acid, it would undoubtedly be better, after extracting the fat, 

 to steam or roast it, in order that it may be easily pulverized. 

 Raw, untreated leather is ground only with difiiculty, and if 

 the mechanical condition of the leather were poor, the action 

 of the sulphuric acid would be imperfect. 



Pot Experiments with Dissolved Leather. 

 By J. B. LiNDSEY AND R. H. Smith. 



In oi-der to still further study the availability of the nitro- 

 gen in dissolved leather, pot experiments were instituted, 

 and the result of our first year's trial is here presented. 



The Pots vsed. 



The pots were made of thin galvanized iron, and were 

 seven and three-quarters inches in diameter and eight inches 

 deep. A galvanized-iron tube, half an inch in diameter, 



