70 FERTILISERS CONTAINING NITROGEN [chap. 



so small and irregular are the parcels from which any 

 bulk of soot is made up. 



Another group of substances which practically are 

 purely nitrogenous manures are the shoddies and kindred 

 products derived from textile industries and other trades 

 dealing with silk, wool, hair, fur, or skin. Properly 

 speaking, shoddy should consist of the short, broken 

 fragments of wool which are rejected in the various 

 processes for preparing woollen fabrics because they 

 arc not long enough to make up into >arn, but now 

 the term is applied more generally to any form of 

 waste from silk or wool manufacturing which is no 

 longer profitable to work up for cloth. The material 

 is thus extremely valuable in composition ; pure wool 

 contains over 17 per cent, of nitrogen, pure silk about 

 as much, and at one end of the scale of shoddies come 

 materials like carpet waste, cloth clippings, and gun wad 

 waste, which are nearly pure and may contain as much 

 as 14 per cent, of nhrogen. Less valuable, because of 

 the greater admixture of dirt, are wool combings, flock 

 dust, and other cloth wastes where cotton is also used, 

 these may have 5 to 10 per cent, of nitrogen ; while lower 

 still come the manufacturing dust from textile factories, 

 the sweepings of workshops, etc., in which the nitrogen 

 may fall as low as 3 per cent. 



Closely allied to such shoddies are hair and fur 

 waste, skin waste, rabbit flick (ears, tail, feet, etc., and 

 other fragments of rabbit skins), feathers, ground hoofs, 

 horn shavings, and leather dust. 



In all these materials the nitrogen exists in very 

 complex compounds of carbon, insoluble in water, and 

 requiring to pass through several stages of bacterial 

 decomposition before they reach the plant. In conse- 

 quence of their very variable composition and character 

 it is impossible to make any general statements about 



