DEATH ON PLANTS. 329 



been noticed a crude article of a reddish or brown color, which 

 in several instances has been traced back to an English estab- 

 lishment. This crude sulphate of ammonia contains quite fre- 

 quently varying quantities of a poisonous ammonia compound, 

 which is known to chemists by the name of rhodan or sul- 

 phocyan ammonium. 



The presence of this injurious compound is due either to a 

 faulty process of manufacture, or to a direct evaporation to 

 dryness of the mother liquor from which the crystallized sul- 

 phate of ammonia has been gathered, instead of separating 

 the ammonia from the residual solution by means of lime. 

 In one instance the entire crude compound consisted mainly 

 of 73.94 per cent, of crude ammonia and 14.87 per cent, of 

 sulphate of ammonia. 



Sixty pounds of that article applied to one acre of meadow 

 land in Germany destroyed the entire grass crop. Thirty- 

 eight pounds of that same material added to a superphosphate 

 used upon one acre of land turned to account for the produc- 

 tion of potatoes, reduced the yield to one-third as compared 

 with the effect of the same amount of superphosphate without 

 that spurious ammonium sulphate. Of still later date is an 

 interesting observation regarding its effect on barley. Seventy- 

 five pounds of an English ammoniated superphosphate contain- 

 ing 10 pounds of soluble phosphoric acid and 7 to 8 pounds 

 of nitrogen was applied per acre at this low rate, for the cul- 

 tivation of barley. 



The seed germinated very slowly ; the young germs were 

 of a yellowish white color ; the entire young plants were 

 very feeble and the majority of them soon died out. The 

 presence of rhodan ammonium in the sulphate of ammonia 

 may be easily proved by dissolving a small quantity of that 

 substance in water and adding a few drops of sesquichloride 

 of iron, which produces in that case a deep red color. 



The price of a good sulphate of ammonia has been from 

 4| to 4| cents per pound in case of 25 per cent, of ammonia 

 or 20.6 per cent, of nitrogen. 



42 



