68 



Use of Waste Organic Substances. [may, 



grease. Clean samples, derived from butchers' fat and the 

 trimmings of joints, are used as food for dogs, pheasants, and 

 poultry ; lower grades, obtained in melting down grease from 

 other sources, are available as manure, and have been effectively 

 used on hops, fruit, wheat, and other crops. The composition 

 varies, and the fluctuation in price is considerable, 50s. to £S 

 being perhaps the outside figures, but it is not difficult to fix a 

 maximum value for a particular sample, because of the close 

 relationship between greaves and meat guano. The latter 

 article consists of well-dried and finely-ground greaves mixed - 

 with bone meal ; as a manure it is superior to ordinary roughly- 

 ground greaves, and a higher price may reasonably be paid for 

 the ammonia it yields. At present meat guano is being offered in 

 Kent and Surrey at los. to 13s. per unit for ammonia and is. per 

 unit for phosphate ; it should be used in preference to greaves 

 unless there is a distinct difference in price. The prices asked 

 for greaves are sometimes excessive : a sample yielding 5 per 

 cent, of ammonia and 5 per cent, of phosphate, and worth, on 

 the above basis, from 50s. to 55s., was offered to the Wye 

 College at £s • -^'^ doubt the varied uses of greaves as food, 

 for meat guano, and as an ingredient of certain mixed manures 

 had to do with the high price, which was asked in good faith 

 by a local dealer. 



Hair {Calf Hair, Hair Waste). — This yields about 12 per 

 cent, of ammonia, but it does not easily decompose in the soil. 

 As a rule the mechanical condition is very bad ; the hair is 

 matted in lumps which resist all ordinary farm appliances and 

 absolutely refuse to break down. They may be in the soil for 

 an indefinite time without perceptibly diminishing. I have 

 known calf hair remain for two years in a hop garden and at 

 the end of that time still yield 12 per cent, of ammonia when 

 brought to the laboratory. 



Having regard to its unsatisfactory mechanical condition, hair 

 must be valued at less than feathers and much less than meat 

 guano. I am inclined to think that 4^. or 5s. per unit of 

 ammonia is fully as much as it is worth ; this would make its 

 value about 50s. or 60s. per ton, At the same time, if it could 

 be supplied in a finely divided state it would be worth more ; as 

 it is, a higher price is often paid for it. 



Hoofs and Horns,~-ThQ value of these is regulated mainly by 



