216 BOAED OF AGRICULTURE. 



had enough else to do, and part of it was connected with the 

 manufacture of a respectable superphosphate. I felt some as 

 Neheniiah did, when invited to come down from the wall he was 

 building, and hold a conference on the subject. He felt that the 

 wall was worth more than talk about walls ; and I thought the 

 making of a good superphosphate was the best answer to the 

 article. You can judge, nearly enough, what reply I would deem 

 appropriate to most of its allegations, but 1 will remark in relation 

 to the diligence of search for a good superphosphate, said to have 

 been made, that I can conceive of no obstacle which need prevent 

 one possessing ordinary locomotive powers, in the usual condition of 

 the streets of Boston, in less than ten minutes' walk from the office 

 of the Journal of Chemistry, from reaching several places where 

 a ton or a hundred tons of good quality could be had at a fair 

 price. 



It seems strange, too, that it never occurred to the Doctor that 

 the "strong odor" might possibly have had another origin than 

 from "dead cats and dogs." In one superphosphate extensively 

 sold, a strong, garlicky smell is due to the addition of ammoniacal 

 products obtained from the 'destructive distillation of bones in the 

 manufacture of bone charcoal ; and an effective addition it is, — 

 rendering it more stimulating to vegetation. In the superphos- 

 phate of the Cumberland Bone Company is an addition made for 

 the purpose of rendering it repellantto vermin in the soil infesting 

 plants, like wire-worms, onion maggots, etc. But the chemistry of 

 the article quoted, and its arithmetic, are fairly open to criticism. 

 The writer says that "there ought to be only one kind of super- 

 phosphate, and that a genuine superphosphate of lime, containing 

 at least ten per cent, soluble jiliosphoric acid, and an equal quantity of 

 insoluble in addition to the phosphate of lime.'' 



Ten per cent, soluble and an equal quantity of insoluble make 

 twenty per cent. Bear this in mind, and then note that lower down 

 he tell us how to make just this same " genuine superphosphate." 

 He says " To manufacture such all that is required is to dissolve 

 fine bone dust in oil of vitriol — one hundred and fifty pounds of the 

 former to eighty pounds of the latter ;" (with the addition of water, 

 &c., but as the water mostly dries out again, though some is retained 

 in combination, we will not count that in). The product of super- 

 phosphate weighs one hundred and fifty pounds, (for the bone) plus 

 eighty pounds acid, making two hundred and thirty pounds at the 

 least. Now, bones contain one half their weight of phosphate, 



