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stitute for i ton of farmyard manure and the two manures may 

 be used mixed together. Oil-cake is more effective in moist 

 soil and in wet weather than in dry soil and in dry weather, 

 Rape cake, neem-seed-cake and castor- cake are-specially valu- 

 able as they inhibit the attack of insects. Rape-cake contains 

 3i to 5 per cent, of N, i| to 3^ per cent, of P 2 O 5 and twothirds 

 of this latter quantity of K 2 O, the total ash being 4^ to 7^ 

 per cent. Castor oil-cake, mustard-cake and mahua-cake are 

 poisonous to cattle. 



86 r. Sugar-cane refuse (called ( megass') is a fairly 

 good manure as it contains '5 per cent, of N, Refuse from 

 sugar-refineries i. e. bone-charcoal containing albuminoid 

 and other impurities, is a very good manure, especially if it is 

 used powdered first in closets and the night-soil mixed up 

 with this powdered charcoal used as manure. The utilisation 

 of bone-charcoal refuse of sugar-refineries in a powdered state 

 by municipalities and its subsequent use for cropping in 

 trenching grounds would be a great agricultural and sanitary 

 improvement. 



862. Coal contains i per cent, of N. which occurs in a 

 very inert form to be of much manurial use. In process of 

 distillation in gas works, however, about Jrd of this is convert- 

 ed into NHg. some into CN, some into organic bases such as 

 aniline, a considerable portion being left in the coke, and a 

 little is given off as free N. With the addition of H 2 SO 4 the 

 ammonical liquor is evaporated and the residue is (NH^sSO^. 

 This crude ammonium sulphate of gas-works contains ammo- 

 nium chloride and ammonium thio-cyanate. This last named 

 constituent is poisonous to plants and the crude ammonium 

 sulphate is, therefore, re-crystallised and purified before it is 

 sold. The ammonium sulphate of commerce contains 24 to 

 25 per cent, of NH 3 . When pure, (NH 4 ) 2 SO 4 contains 25'5/ 

 of NH 3 . The ammonical liquor of gas works contains about 

 2\ per cent, of NH 3 i. e. about 4 ounces of NHs per gallon. 

 Each ton of coal distilled produces 10 gallons of liquor, 

 PPP 



