Annual Report of the Consulting Chemist, 281 



a good deal of greasy matter, like that made from green bones, 

 it takes some time before the water is absorbed. It is desirable, 

 therefore, to pour at once upon the bone-dust about half its 

 weight of water, and after a lapse of six or eight hours to turn 

 over the heap, and to add some more water, if necessary, at the 

 same time. According to the state of dryness of the bone-dust 

 it will absorb in the course of eight or twelve hours from one-half 

 to two-thirds its own weight of water. On the following day 

 the wetted bone-dust may be mixed with mineral superphosphate 

 in the proportion of one of bone-dust to two or three of mineral 

 superphosphate. By putting up the mixed manures in as com- 

 pact a heap as possible, in about twenty-four hours the wetted 

 bone-dust will ferment and set up a considerable amount of heat 

 in the heap ; and, attracting the acid from the mineral super- 

 phosphate, it will become still further broken up, or, at all events, 

 softened and rendei'ed more efficacious as a manure. The com- 

 post of bone and superphosphate may be turned over after 

 having been kept undisturbed for about a fortnight ; but, if time 

 permits, it is better to allow three or four weeks before the heap 

 is turned over ; for by keeping the compost during the longer 

 period, the bone is more th(noughly reduced to a fine state, and 

 the bone superphosphate is obtained in a drier condition than is 

 the case if the bone compost is turned over after it has been put 

 up for only a fortnight. 



There is no difficulty in ascertaining, by simple inspection, 

 whether ^ or ^ inch bones are genuine or not. The super- 

 phosphate should be bought merely as a source of soluble 

 phosphate, on the strength of a guarantee which secures to the 

 purchaser a superphosphate containing, say, 25 per cent, of 

 soluble, at a fixed price, for each unit per cent. At 'Ss. GfZ. per 

 unit of superphosphate, a superphosphate guaranteed to contain 

 25 per cent, of soluble phosphate would be worth — 25 X 3^. 6^/., 

 4Z. 7^. Gd. a ton. At that rate soluble phosphate may be bought 

 in most places ; but it is impossible for a farmer to obtain it at 

 so cheap a rate from bone-dust. It is therefore good economy to 

 buy soluble phosphate in the shape of mineral superphosphate ; 

 and by mixing with it a certain proportion of bone-dust, 

 previously wetted by water, a dry, fine home-made bone super- 

 phosphate, which, unlike purchased bone superphosphate, leaves 

 no uncertainty whether the insoluble phosphates are contained 

 in the manure as bone or as mineral phosphate, can be prepared 

 on the farm without much trouble. In this way a better turnip- 

 manure may be obtained at a less expense than when "dis- 

 solved bones ' or bone superphosphate are bought from manure- 

 <lealers. 



The samples of nitrate of soda, sulphate of ammonia, bone 



