FIBROUS WASTE PRODUCTS 121 



waste products are frequently derived from the textile industries, 

 and comprise wool, silk, hair, and fur wastes. They vary greatly in 

 quality, and a true shoddy consisting of waste short-slaple wool may 

 contain 14 per cent, or over of nitrogen, whereas wool and flock 

 dusts, factory sweepings, etc., may be so mixed with dirt as only to 

 contain 3 or 4 per cent, of nitrogen. The " shoddies " also vary 

 considerably in value. 



Besides these materials there are also cloth and rag wastes, 

 skin waste, feathers, hoof and horn shavings, rabbit flick, slaughter- 

 house refuse, leather cuttings and dust, and many others. This 

 latter class is generally much less valuable than the fibre wastes, 

 being less readily decomposed in the soil and usually much coarser 

 in texture. 



105. Qualitative Examination of Fibrous Waste 

 Products — Shoddies y etc. 



(a) Mechanical condition. — The texture of the 

 material should be carefully noted, and any obviously 

 extraneous matter picked .out and examined 

 separately. 



{b) Sandy matter. — If no analysis is to be carried 

 out (see below) the material should be well fingered, to 

 detect sand, and a few grams ignited and the residue 

 examined ; it should be grey or practically colourless 

 in appearance if purely animal or vegetable in character, 

 and as a rule only if mixed with mineral substances will 

 it contain much iron and have a reddish colour. 



{c) Oil. — The presence of much oily matter may be deleterious 

 and prevent the bacterial decomposition of the manure. Large 

 quantities may be detected as follows : — 



A few grams of the manure are twice shaken up 

 with ether in a tube, the ethereal solutions united and 

 filtered, and then allowed spontaneously to evaporate. 

 The oily residue, if any, may be examined by the tests 

 described in 13, 14, pp. 22, 24. 



{d) Nature of the Fibre. — Wool and silk, consisting of almost 

 pure protein (17 per cent. N), are the valuable constituents of 



