IV.] DISSOLVED BONES 113 



form of applying phosphates; a mixture of steamed 

 bone flour and superphosphate left for a few days 

 in the mixing shed and then broken down again 

 is also very useful on such land. 



Dissolved bones also represents a manure which at 

 one time had a much greater vogue than it possesses 

 at the present day, when it is no longer admitted 

 that superphosphate made from bone possesses any 

 superiority over the same compound made from 

 mineral phosphates, except in so far as the bone 

 manure also contains nitrogen. Dissolved bones or 

 bone superphosphate generally contains from 35 to 40 

 per cent, of phosphate, of which from 12 to 18 will 

 usually be in a soluble condition ; while the nitrogen 

 amounts to about 3 per cent. 



Dissolved bones forms a brown mass generally 

 somewhat damp and sticky, and not rubbing down 

 into a convenient powder for sowing; it is, in fact, 

 impossible to get it into a dry friable condition 

 without some admixture of " dryers " like gypsum, 

 which are not considered as admissible. The trade 

 in dissolved bones usually proceeds on a guarantee 

 that it contains pure bones and sulphuric acid only, 

 though it is difficult to demonstrate that such a 

 product possesses any intrinsic superiority over any 

 other manure mixture compounded so as to show 

 the same composition. Such mixtures are furnished 

 by the bone compounds and bone manures, which 

 are often mineral superphosphates mixed with more 

 or less superphosphate made from steamed bone 

 flour, with a little extra nitrogen derived from dried 

 blood, fine shoddy, or even sulphate of ammonia. 

 Such compounds are useful enough if they are cheap ; 

 before purchase they should be valued on the basis of 

 their analysis and judged accordingly^ 



H 



