1906.] Use of Waste Organic Substances. 



67 



provided the mechanical condition is satisfactory, these substances 

 have more value than our text-books would have us believe. 



The prices quoted in this paper are those which the practical 

 hop grower in a position to make favourable purchases finds it 

 worth his while to pay. 



The substances dealt with fall into three groups : — 



1. Residues from animal carcases : Dried blood, feathers, 

 greaves, hair waste, hoofs and horns, rabbit waste, slaughter- 

 house refuse. 



2. Residues from manufactures : Damaged cakes, shoddies, 

 tannery waste. 



3. Residues from towns : Destructor refuse, night soil, 

 poudrette, sewage sludge. 



I. Residues from Animal Carcases. 



Dried Blood. — Without doubt this is an excellent fertilizer, 

 and it is used by some manufacturers for their mixed manures. 

 The price at which it is offered to farmers appears usually too 

 high, in consequence, it is understood, of competition from 

 America and the Continent. Thus a sample yielding 12 per 

 cent, of ammonia was offered at ^8 delivered in Kent, which 

 works out to a unit price of 13s. 4d. The latest quotations 

 seen have been even higher. 



Feathers and Feather Waste. — Excellent results are obtained 

 in some hop gardens by using about 20 to 25 cwt. of feathers, 

 and the limited supply (amounting probably to only a few 

 hundred tons a year) is rather keenly sought after. Large 

 feathers are slow in action, the shafts especially taking a long 

 time to decay ; a sample containing many of them is not as 

 valuable as one composed mainly of small, more easily decom- 

 posable feathers. The ammonia obtained is usually a little over 

 10 per cent., a not uncommon price being ^5 per ton delivered, 

 giving a unit price of los. In spite of the generally good 

 mechanical condition, one cannot help thinking this is too high. 

 The price naturally fluctuates ; farmers have been known to 

 pay 15s., while samples have also recently been offered at 

 70s. to 80s. At these lower prices, where the unit value is 7s. 

 to 8s., feathers must be considered cheap. 



Greaves. — Etymological ly this word is the same as "gravy " ; 

 it denotes the refuse or sediment left in making tallow or soap 



