540 AGRICULTURE. 



surrounding soil. There are, in most countries, large quantities 

 of mineral phosphates, notably in Canada and Spain, but 

 no great deposit is so favorably located, with regard to com- 

 merce, as that of South Carolina. One of the most important 

 sources of phosphate for agriculture is, and must continue to be, 

 animal bone ; not, as has been by many supposed, that the phos- 

 phate of animal origin is more valuable than that of mineral 

 origin. 



The great and increasing exportation of our live-stock is 

 deporting from our fields vast and increasing quantities of phos- 

 phates. The wise and well informed would be glad to see this 

 trade replaced by a normal home consumption of meat, by our 

 own working people and the great middle class, which is ren- 

 dered impossible under existing financial and industrial condi- 

 tions. The time will come when the phosphate thus exported 

 will have to be brought back to us, if our wheat area is to pro- 

 duce bread sufficient for our own people. 



Many will still dissent from the remark just made, that phos- 

 phate of mineral origin is fully equal, as a fertilizer, to that of 

 animal origin ; but the fact has been fully demonstrated, in a 

 series of field trials, conducted by Professor Jaimison on behalf 

 of the Highland and Agricultural Society of Scotland ; which 

 experiments, for scientific accuracy and fulness of detail, can- 

 not be surpassed. These same experiments have established 

 the fact that, instead of the tribasic, or insoluble, phosphate 

 being classed with sand and water, as not " available " to plants 

 and worthless as a fertilizer, the dissolved phosphate does not 

 exceed it by more than 10 per cent, in the increase of crop 

 produced. 



The question is no longer whether tribasic phosphate is 

 "available" to plants, but how much its "availability" is in- 

 creased by the usual treatment with sulphuric acid, converting 

 it into superphosphate. The answer to that question, according 

 to present information, is not exceeding 10 per cent. That 

 is, if a ton of raw phosphate will produce increase of crop worth 

 $10, the same phosphate, subjected to the usual treatment, will 

 produce increase worth $11. The manipulation consists in the 

 addition of a ton of sludge acid, and of about 500 pounds of 

 sodium chloride, as drier. Thus the one ton of raw phosphate, 



