112 PHOSPHATIC MANURES [chap. 



of the nineteenth century. Large dressings of bones 

 were employed — a ton or more per acre — and the 

 application was expected to last for twenty years, 

 little return being obtained during the first year or 

 two ; for this reason the landlord contributed freely 

 to the cost of boning, even if he did not pay for it 

 entirely. The pastures improved steadily after the 

 dressing of bones ; in particular, such a growth of 

 white clover was encouraged that farmers began to 

 suspect the manure contained clover seed, a supposition 

 which was repeated fifty years or more later when basic 

 slag first began to be used on clay pastures. At one 

 time bones and bone meal were subject to a good deal 

 of adulteration, often of the most flagrant description ; 

 nowadays, however, there is very little admixture of 

 foreign substances with bone meal. Occasionally mineral 

 phosphates may be used to raise the percentage of phos- 

 phoric acid, or the bone meal may be represented as 

 richer than it is, but these frauds are at once detected 

 on analysis, which indeed should never be omitted 

 because of the natural variations in the material. 



If bone meal is still somewhat overvalued on account 

 of the long experience farmers have had of its value, 

 on the other hand, steamed bone flour hardly gets 

 justice done to it. Its deficiency in nitrogen is regarded 

 as a defect, but when steamed bone flour is considered 

 merely as a phosphatic manure, its finer grinding and 

 freedom from cartilage render it more available than 

 bone meal ever can be. The experiments of the High- 

 land and Agricultural Society during 1 890-1 have shown 

 it to be about the most suitable of all the phosphatic 

 manures for the turnip crop on light soils which are too 

 poor in lime for superphosphate and too short of water 

 for basic slag. For the sands and gravels, a neutral 

 easily soluble manure like steamed bone flour is the best 



