80 FERTILIZERS. 



tar in chimneys. Owing to its richness in ammonia, and 

 the facility with which, when steamed under pressure, it 

 granulates into a fine blood-colored powder, or readily 

 grinds up after being charred, it has been largely used by 

 ignorant or unprincipled manufacturers as a source for 

 nitrogen in their fertilizers, several of the States having, 

 until recently, required by law the per cent of nitrogen, 

 without designating in what form it should or should not 

 be. The gelatine present, though rich in ammonia, is 

 rendered by the tannic acid nearly insoluble, and hence 

 for aimual crops is practically worthless. This adultera- 

 tion has been carried on to a far greater extent than the 

 public is aware. Tens of thousands of tons have been so 

 disposed of, as I have been informed by those behind the 

 scenes. In the Massachusetts Agricultural Report for 

 1882, it is stated that leather scraps were offered in Boston, 

 early in the season, in a fine state of subdivision, at $5.50 

 per ton ; but later, in the month of May, they advanced to 

 $15 per ton. The cause of this advance, it would require 

 no great wit to perceive. It is said that from four thou- 

 sand to five thousand tons were sold in and about Boston 

 that year, to be used in the manufacture of fertilizers. If 

 every State would require the dealers to state the source 

 from which their nitrogen was obtained, the adulteration 

 would soon cease, for every chemist has at hand the 

 means of detecting its presence. Though the process is a 

 slow one, leather scraps, even the coarsest, from sole 

 leather, will eventually decay ; but this fact gives no value 

 to them for the growing of annual crops, for they need to 

 be years in a mass before they will turn black and rot. I 

 have used tons of them around currant-bushes, where 

 they serve to keep down weeds, and in the course of years 

 entirely disappear, becoming plant-food. If used into 

 tillage-land, they become a nuisance, for more or less of 



