BONEBLACK AND ITS VALUE. 259 



phosphatic fertilizer at a reasonable cost. Applied in time, 

 they are more reliable in their influence on the crops than the 

 common class of superphosphates, for the quality of the soil 

 interferes, as a general rule, less with their action, than with 

 that of the superphosphates. 



BONEBLACK WASTE. 



The sample was secured at the storehouse of Messrs. Bagg 

 & Batchelder, Springfield, Mass. ; it contained 33.71 per cent, 

 of phosphoric acid, which is equal to 73.60 percent, of bone- 

 phosphate or tricalcic phosphate. A boneblack waste, like 

 the one here stated, sells at $30 per ton. One pound of phos- 

 phoric acid sells thus, in that form, at 4.5 cents. Boneblack 

 waste for agricultural purposes is best changed into a super- 

 phosphate. 



Dissolved Boneblack. 



This name was given to a concentrated superphosphate 

 obtained by the treatment of boneblack with a sufficient 

 amount of sulphuric acid to render the entire amount of phos- 

 phoric acid present soluble in water. The article tested was 

 collected at the storehouse of Messrs. Bowker & Co., Boston, 

 Mass., where it served as a source of soluble phosphoric acid 

 for the manufacture of compound commercial fertilizers. It 

 was represented to contain from 14 to 16 per cent, of soluble 

 phosphoric acid. The analysis proved that 15.03 percent, of 

 phosphoric acid was soluble in water ; the insoluble phos- 

 phoric acid present amounted to 0.8 per cent. The article 

 sold at $36 per ton of 2,000 pounds, or 12.5 cents per pound 

 of soluble phosphoric acid. 



Caribbean Guano. — ( Orchilla . ) 



Phosphoric acid, 27.12 per cent. 



Calcium oxide, 34.91 " 



Magnesium oxide, 2.63 " 



Sulphuric acid, 2.36 " 



Moisture (at 100° C), 12.50 



This mineral phosphate consists of phosphate of lime, sul- 

 phate of lime, carbonates of lime, and magnesia, with some 



