THE GENESEE FARMER. 



ical possibility, in 'Mapes' improved,' 20.98 per cent. /ree ^wZpAttnc a«c?. * * When 

 we find sucli an analysis we can not but have doubts respecting the ability and expe- 

 rience of the analyst." This, we presume, is the error which Mr. Mapes said lay so 

 plainly on the face of the analysis. Let us examine it a little. It is true that phos- 

 phate of lime and sulphuric acid can not be brought into direct chemical contact 

 without decomposition. For instance : were both in solution it would be " against all 

 chemical possibility" to find free sulphuric acid and undecomposed phosphate of lime. 

 But in a dry mixture, as when calcined bones and sulphuric acid are mixed together, 

 this direct chemical contact does not necessarily take place, and consequently the sul- 

 phuric acid and phosphate of lime may exist in such a mixture without chemical action. 



We recollect once trying to convert " half-inch bones" into superphosphate of lime. 

 The bones were first moistened with the proper quantity of water, and then sulphuric 

 acid, at intervals, added in sufficient quantity to more than convert the whole into super- 

 phosphate. The mixture was well and thoroughly stirred, and occasionally turned over 

 for two months, yet not half the bones were acted on by the sulphuric acid — the outside 

 of the bones merely were decomposed. Does any one suppose that in such a mixture 

 it is " against all chemical possibility" for free sulphuric acid and undecomposed phos- 

 phate of lime to exist ? 



Again : When conducting some experiments on a large scale in the Rothamsted 

 laboratory on the manufacture of superphosphate, we found that it was impossible to 

 make a good manure unless the substance used was ground to an impalpable powder. 

 Thus, animal charcoal, (we presume the article which Mr. Mapes uses in the manufacture 

 of his manure,) we found could not be decomposed unless firrely ground. We have 

 used 100 lbs. of sulphuric acid to 100 lbs. of animal charcoal, and had still, "against 

 all chemical possibility," after well stirring and allowing it to remain a sufficient length 

 of time, a considerable quantity of undecomposed phosphate and/ree sidphiwic acid. 



About fifteen months ago we had sent us a sample of " Mapes' improved superphos- 

 phate of lime. Judging from appearances we thought that the article was manufactured 

 from the unground animal charcoal, and that not more than half of it was acted on by 

 sulphuric acid — a conclusion we afterwards found to be correct from an analysis by Dr. 

 Antisel. We have no doubt this article contained free sulphuric acid, as it most cer- 

 tainly did undecomposed phosphate. Since then we have seen other samples of Mapes' 

 "improved," and conclude that he now grinds his animal charcoal ; at all events, it is 

 now a much better manufactured article — yet still it is not only possible, but we think 

 quite probable that it contains free sulphuric acid as well as undecomposed phosphate 

 of lime. So much for the third error of Mr. Johnson. 



The fourth mistake is thus set forth. Speaking of Mr. Johnson's analysis, our critic 

 says : " We in vain ask, Where are the constituents of guano, the oxalic, uric, hydro- 

 chloric acids, which in Mapes' are present in the form of water, oxalate of ammonia, 

 chloride of ammonium, and oxalate of lime? Where is the potash, the urea capable of 

 being converted into carbonate of ammonia? Where is the sulphate of ammonia, 

 which is present in large quantities in the improved superphosphate ?" A fine piece of 

 rhetoric this. Dr. EndePvLin ! You are an adept at mystifying a subject, and at showing 

 off" your profound learning to your agricultural readers ! We would ask. Is your oxalic 

 acid, chlorine, the carbon and hydrogen of urea compounds, (fee, of much agricultural 

 value ? We have been in the habit of considering them of little worth. Are we mistaken ? 

 We had supposed that if you knew the amount of ammonia or nitrogen a compound 

 contained, you were in possession of all that was necessary to determine the amount 

 and value of its urates, urea, oxalate, and other salts of ammonia. 'This Mr. Johnson 

 has determined. He found that ' Mapes' improved' contained 15.80 per cent, of organic 

 matter and salts of ammonia, and that this organic matter, <fec., contains 2^ lbs. of 

 ammonia ; the other 13^- lbs. of organic matter contain your oxalic acid, carbon, hydro- 



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