68 THE CONNECTICUT AGRICULTURAL 



which results from the granulation goes to the superphosphate 

 manufacturers, and is one of the best materials for their use. 

 When the granulated bone-black has been used in decolorizing a 

 certain amount of sugar it loses its efficacy and is subjected to a 

 red heat in close pots in order to restore (partially), its defecating 

 power. After some repetitions of this process it becomes of no 

 further use to the sugar refiner and goes to the fertilizer maker. 

 This " spent bone-black" is less valuable than the refuse powder, 

 above mentioned, because its phosphoric acid is reduced by five 

 to ten per cent., and the carbonates considerably increased. The 

 demand for bone-black on the part of fertilizer makers is so great 

 that unwholesome stories are in circulation to the effect tliat infe- 

 rior native phosphates, under false colors, i. e., suitably blackened, 

 are in the market carrying the name and style of bone-black but 

 in fact and with intent spurious, although not altogether worth- 

 less. 



I will add here an estimate of the commercial value of the 

 product that would result from the quantities of bones, wood- 

 ashes, etc., used in IlienkofF's process as above described : 



4,000 pounds of average bones contain 4 per cent, or 160 

 pounds of nitrogen and 20 per cent, or 800 pounds of phosphoric 

 acid. 



4,000 pounds of average wood ashes, unleached, contain 8^ per 

 cent, or 340 pounds of potash, and 2 per cent, or 80 pounds of 

 phosphoric acid. The bones and ashes together contain — 



160 pounds of nitrogen, worth, at 20 cents, ..- $32.00 



880 " phosphoric acid, worth, at 9 cents, 79.20 



340 " potash, worth, at 5^ cents, 18.70 



$129.70 



Admitting that there is no loss of nitrogen and no loss or gain 

 of water or of loam, etc., this value of §129.70 would belong to 

 13,100 pounds or 6| tons of the finished bone compost. The 

 value of one ton would accordingly be, in round numbers, $20. 



Preparation of Bone Superphosphate. 



In answer to repeated inquiries from various sources, the method 

 of " dissolving " ground bone, i. e. of preparing a bone superphos- 

 phate by help of sulphuric acid — useful where soluble phosphoric 

 acid and nitrogen are desired — is here given. 



