THE SOUTHEEN PLANTER. 



295 



water was found to be twenty-eight (28) per cent. — 

 of tJiis nearly two parts were phosphoric acid, viz : 



valuable elements soluble in water. 



Phosphoric acid 1.81 



Potash of soda 2.00 



Volatile compounds, containing ammonia 16.15 



Sulphuric acid, lime, magnesia and other 



elements of less importance 08.04 



28.00 



RECAPITULATION. 



Total proportion (per cent.) of valuable elements 

 in this " chemical manure''' — 3.75 or nearly four per 

 cent, of nitrogen, equal to 4.51 or nearly five per 

 cent, of ammonia; 18.63 or nearly nineteen per cent, 

 of phosphoric acid, equal to 38.40 per cent, of bone 

 phosphate of lime, or nearly 39 per cent.; 1.81 or 

 nearly 2 of this phosphoric acid is soluble in water, 

 and is, therefore, equivalent in its effects of five 

 times the bone phosphate of lime that it represents. 

 See Patent Office Report, 1852-3, Agricultural, p. 

 391. 



Making the most liberal allowance as above, and 

 estimating bones to be worth S25 per 2000 lbs. (ton) 

 we may say that in considertion of the soluble phos- 

 phoric acid, the phosphates in this compound are 



worth, per ton S25 00 



And the ammonia 10 00 



Whereas, if we estimate the phosphates in Peruvian 



guano at same rate the 500 lbs. of phosphates in 



Peruvian guano Avould be $V1 50 



And the 320 lbs. of ammonia in a ton of 



Peruvian guano would be 35 24 



$4:1 74 



In view of the above analysis, I do not hesitate 

 to say that this manure is cheaper to many farmers 

 at forty dollars per ton, than Peruvian guano at 

 fifty, and believing as I do, that there is no species 

 of manure for any crop, and much less for all soils, 

 I still reiterate the opinion expressed several years 

 since, that these combinations of Peruvian guano 

 are more generally certain than the Guano alone, 

 which fails on many farms to produce any good 

 effect. 



I have given its absolute value or money value — 

 also my opinion of its price — and it is my intention 

 to apply one ton to my corn field this year where 

 its use is indicated, and where I am sure it will 

 compare favorably with any other manure. 

 Respectfully, 



David Stewart, M. D. 

 Balthnore, 79 North Eutaw Street. 



We see at first siglit that the above does not 

 represent a super phosphate at all. Where is 

 the necessary sulphuric acid ? This is a ques- 

 tion which the analysis cannot answer. 



We read in one place : 



" Salts, potash and soda, sulphuric acid, &c. 

 / 5.55," and at another: 



" Potash and soda." 



Now if potash and soda make 2 per cent, 

 by themselves, then, of course, salts of potash 

 and soda must make at least 5 per cent. De- 

 i duct these 5 per cent, from the whole amount 

 allowed for salts, potash and soda, sulphuric 

 acid, &c., which is 5.55 as above mentioned, 

 and we have half of one per cent, for sulphuric 



acid, &c., and therefore in a favorable case one- 

 fourth of one per cent, of "&c." and one-fourth 

 of one per cent, of "sulphuric acid." This 

 amount of sulphuric acid is so small as must 

 be considered an incidental impurity, and not 

 as the agent which had transformed common 

 phosphate of lime into a soluble bi-phosphate 

 or super phosphate. 



The analysis mentions 1.8 per cent, of solu- 

 ble phosphate acid : this cannot be attributed 

 to the action of sulphuric acid on the original 

 phosphates. Nobody need, however, be asto- 

 nished at its presence who knows the action of 

 ammoniacal salts on phosphates. Ammoniacal 

 salts, especially sulphate of ammonia, dissolve 

 pretty readily phosphate of lime and to this 

 fact the great effect of Peruvian guano must, 

 to some extent, be attributed. Peruvian gua- 

 no, as we know, contains phosphate of lime be- 

 sides ammonia; if this article is mixed with 

 sulphate of lime (plaster of Paris,) or applied 

 to soil which contains originally plaster of Pa- 

 ris, sulphate of ammonia is formed, which acts 

 as a solvent to the phosphate of lime. We 

 even know by experiments, made with mixtures 

 of Peruvian guano and Mexican (pure phos- 

 phate of lime) that the sulphate of ammonia 

 which is formed from 100 lbs. of Peruvian 

 guano makes available not only the phosphate 

 of lime vv^hich these 100 lbs. contain, but that 

 it acts also on additional qualities of phosphate 

 of lime, which the Mexican guano contained, 

 and that for this reason the application of a 

 mixture of Peruvian guano and Mexican is in 

 all cases far more economical and rational than 

 the application of Peruvian guano alone, pro- 

 vided that the soil is deficient in phosphoric 

 acid. 



Dr. Stewart shows ammoniacal salts to be 

 present in C. B. DeBurg's Super Phosphate of 

 Lime, and the presence of 1.8 per cent, of so- 

 luble phosphoric acid must, therefore, be the 

 consequence of the action of these ammoniacal 

 salts on phosphates; the absence of sulphuric 

 acid or any other stronger acid than phosphoric 

 excludes every other reason for its presence. 

 But if this is the case (and no other case is 

 possible from the analysis) we will at oDce per- 

 ceive a great mistake as to the valuation of the 

 article. The value of the ammoniacal salts 

 contained in the article is first estimated, then 

 the value of its phosphates, and finally the va- 

 lue of the soluble phosphoric acid, which esti- 

 mated to be equivalent to five times the pro- 

 portion of bone phosphate of lime that it re- 

 presents. By these means the analyst esti- 

 mates first the agents which are ammoniacal 

 salts and phosphates, and secondly their reci- 

 procal effect which produced soluble phosphoric 



