EXPERIMENT STATION. 67 



and let stand. From time to time add water to keep the mass 

 moist. So soon as iLe bones have softened so that they can be 

 cruslied between the fingers to a soft soap-like mass, take the 

 other 2,00'J pounds of bones and stratify them in another pit with 

 the contents of the first. When tlie whole is soft, shovel out to 

 dry and finally mix Avith dry muck or loam (4,000 pounds), or 

 enough to make it handle well." 



I should suppose that this method might be advantageously 

 modified somewhat as follows: ArrauQ-e a circular laver of bones 

 closely laid on a bed, a foot thick of good loam, under shelter; 

 wet them from a watering pot and sprinkle over them wood ashes 

 enough to fill all the chinks. Then give a coating of gypsum; 

 put upon that a few inches of muck or loam, adding all along as 

 much water as will well moisten the earth and ashes but not 

 more than the mass can easily absorb ; then place another layer 

 of bones with ashes, gypsum, loam or muck, and water as before, 

 until the heap is built up several feet ; finally, cover with loam 

 and keep moist by adding water from time to time, but not 

 enough to run away from the bed. When the bones are suffi- 

 ciently softened, mix well together with the loam used as bed and 

 cover, and with more if need be. This plan would require more 

 time but perhaps would be as efficacious and more convenient 

 than the process last described. 



Instead of wood ashes a mixture of lime and some form of 

 "potash salts" might be employed, but trials on a large scale 

 would be needful to learn the proper proportions and mode of 

 working. 



A third method of disintegrating bones is to induce decompo- 

 sition of the animal matter (ossein), by composting or interstrati- 

 fying them with fermenting horse dung, and kee23ing the mass 

 moist by covering with loam and adding occasionally urine or 

 dung-heap liquor. As to the details of this method or the practi- 

 cability of it, I can give no information. 



Bone-black is prepared by heating bones in close pots or 

 retorts until the animal matter is destroyed and most of it driven 

 off as water, gases, " animal oil " and ammonia. What remains 

 behind in the pots is the " bone-black." It consists of the phos- 

 phate of lime of the bones mixed with some ten per cent, of car- 

 bonate of lime and sand and six per cent, of carbon. The bone- 

 black thus obtained is broken up for use in sugar refining. The 

 refiners mostly employ it in a coarse, granular form. The dust 



