THE SOUTHERN PLANTER. 



263 



phosphates present, as the manure is pre- 

 pared for the express purpose of render- 

 ing the phosphates soluble. Instead of 

 that, however, I found something less than 

 two per cent, of soluble or superphosphate 

 of lime. Whilst filtering the aqueous solu- 

 tion the finer particles naturally ran into 

 the filter first, leaving the coarser ones 

 still in the vessel in which the solution had 

 been made; something peculiar in this 

 residue attracted my attention, and after 

 washing and drying it, I, instead of ana- 

 lyzing it, inspected it carefully with the 

 aid of a powerful eyeglass. I found quite 

 a number of small transparent crystalline 

 plates, which looked very much like the 

 mineral selenite, or crystalined sulphate of 

 lime, (plaster) together with a great num- 

 ber of white grains, which were evidently 

 not particles of bone dust. By the aid of 

 my glass and a pair of forceps, I pinched 

 out and placed in separate piles a number 

 of both crystals and grains and on subject- 

 ing them to analysis, I found them to be 

 selenite and gypsum (i. e. plaster and noth- 

 ing else.) In other words, Mr. De Burg 

 does not add the requisite proport on of 

 sulphuric acid, whereby he would get a 

 large proportion of soluble phosphate, and 

 makes up the deficiency by adulterating 

 his manure with ground plaster. The pro- 

 portion of neutral phosphate I will not de- 

 termine ; I concluded that it could not be 

 precipitated phosphate, as it should be, but 

 must be, the greater part of it — the origi- 

 nal and unaltered bone black: 1st — be- 

 cause the adulteration proves that instead 

 of sulphuric acid having been used in 

 proper proportion, plaster was substituted 

 for it ; and 2nd — if it had been soluble, 

 the use of guano or sulphate of ammonia 

 would not have precipitated it, and ren- 

 dered it insoluble. To put this matter be- 

 yond the possibility of controversy, I took 

 a portion of the superphosphate of lime 

 that had been prepared by myself, and to 

 this I added some guano and sulphate of 

 ammonia, 70 parts of the superphosphate 

 were powdered, and made into a thin paste 

 with 20 parts of guano, and 10 of the sul- 

 phate of ammonia, by which I got a prep- 

 aration containing a higher proportion of 

 ammonia than De Burg's ever contained. 

 The materials having been mixed with wa- 

 ter, even in the most favorable condition 

 for the mutual reaction between the solu- 

 ble phosphates and the substances added, 



and yet no reaction, such as to make the phos- 

 phates insoluble, took place. I determined 

 the proportion of soluble phosphates in the 

 manure by careful analysis and found it to 

 be the same that I would have gotten by 

 calculation, supposing that 30 per cent, of 

 foreign matter had been added without 

 precipitating any of the soluble phosphate 

 of lime. 



I conclude, therefore, that De Burg's 

 superphosphate of lime does not now, and 

 did not when lirst prepared, contain the 

 requisite proportion of soluble phosphates; 

 that the neutral phosphate of lime is prin- 

 cipally, if not entirely, in the condition 

 that we find it in the unaltered bone black, 

 which is the foundation of the manure ; 

 und that the manure is largely adulterated 

 with plaster. I am thus particular in sta- 

 ting facts and my deductions from them, 

 because De Burg's superphosphate has 

 generally been held in high estimation, 

 particularly in the South. 



Mapes' Improved Superphosphate of 

 lime is another manure which has been a 

 good deal used, and is now making loud 

 calls upon the Southern agricultural com- 

 munity; large supplies of it are to be had 

 in Baltimore, and pamphlets containing 

 numerous certificates, analyses, etc , are 

 freely distributed. I obtained a sample 

 from the Baltimore agent, which like De 

 Burg's, may be taken as a fair average of 

 the manure Mr. Mapes and his agents of- 

 fer to Southern farmers. This manure in- 

 stead of being a superphosphate, is, I may 

 say, perfectly destitute of soluble phos- 

 phates, as I could only find traces of phos- 

 phoric acid in the water which contained 

 all the soluble matter of the manure. The 

 pamphlet asserts that it contains 7 per ct. 

 of " actual" ammonia, besides 2 or 3 per 

 cent, of "potential ammonia." I, however, 

 could only find 3 per cent, altogether. In 

 filtering the aqueous solution, I found a res- 

 idue of coarse particles, consisting of bone 

 black, dirt, white grains, &c, somewhat 

 similar to that found in De Burg's. After 

 picking out a number of these white grains, 

 which by inspection with a glass, it was 

 plain was not bqne dust, but some crushed 

 mineral, I soon found them to be carbonate 

 of lime; and since there are large num- 

 bers of them through the manure, I con- 

 clude that it is largely adulterated with 

 that substance., How much soluble phos- 

 phate there was originally, it would be im- 



