BONE-BLACK 



415 



Prior to the use of bones by the turner or carver, they require the oil, -with which 

 they are largely impregnated, to be extracted, by boiling them in water and bleaching 

 them in the sun or otherwise. This process of boiling, in place of softening, robs 

 them of part of their gelatine, and therefore of part of their elasticity and contracti- 

 bility likewise, and they become more brittle. 



The forms of the bones are altogether unfavourable to their extensive or orna- 

 mental employment : most of them are very thin and curved, contain large cellular 

 cavities for marrow, and are interspersed with vessels that are visible after they 

 are worked up into spoons, brushes, and articles of common turnery. The buttock 

 and shin bones of the ox and calf are almost the only kinds used. To whiten the 

 finished works, they are soaked in turpentine for a day, boiled in water for about an 

 hour, and then polished with whitening and water. 



Holtzapffel also informs us that after the turning tool, or scraper, has been used, 

 bone is polished, 1st, with glass-paper ; 2nd, with Trent sand, or Flanders brick, with 

 water on flannel ; 3rd, with whiting and water on a woollen rag ; 4th, a small 

 quantity of white wax is rubbed on the work with a quick motion ; the wax fills the 

 minute pores, but only a very minute portion should be allowed to remain on the 

 work. Common bone articles, such as nail- and tooth-brushes, are frequently polished 

 with slaked lime used wet on flannel or woollen cloth. See ' On Bone and its Uses,' 

 by Arthur Aitkin, ' Trans, of Society of Arts,' 1832 and 1839. 



Bones have recently been imported into this country, from Australia, in the form 

 of bone-dust tiles, made by crushing the bones and compressing the powder into the 

 form of cakes. 



The importance of the trade in bones will be seen from the following statement of 

 imports of the bones of animals and fish not whalebone. 



Bones of all kinds (except Whalefins) imported. 



Quantity 

 Value 



1867 

 Tons 



246,767 

 



437,436 



1868 



Tons 

 245,120 





 430,442 



1869 



Tons 



229,223 





 600,019 



1870 



Tons 



215,748 







629,619 

 Tons 



1871 



Tons 



302,079 







659,416 

 Tons 



1872 



Tons 



BONES, whether burnt. or not for manure . 92,032 94,212 97,778 



BON'XS-BXtA.CK (Noir d'os, Fr. ; Knochenschwarz, Ger.), or Animal Charcoal, as 

 it is less correctly called, is the black carbonaceous substance into which bones are 

 converted by calcination in close vessels. This kind of charcoal has two principal 

 applications to deprive various solutions, particularly syrups, of their colouring- 

 matters, and to furnish a black pigment. The latter subject will be treated of under 

 IVORY BLACK. 



The discovery of the antiputrescent and decolouring properties of animal charcoal 

 in general is due to Lowitz, of Petersburg ; but their modifications have occupied the 

 attention of many chemists since his time. Kels published, in 1798, some essays on 

 the decolouring of indigo, saffron, madder, syrup, &c., by means of charcoal ; but he 

 committed a mistake in supposing bone-black to have less power than the charcoal of 

 wood. The first useful application of charcoal to the purification of raw colonial 

 sugar was made by M. Guillon, who brought into the French markets considerable 

 quantities of fine syrups, which he discoloured by ground wood-charcoal, and sold them 

 to great advantage, as much superior to the cassonadcs (brown sugars) of that time. In 

 1811, M. Figuier, an apothecary at Montpellier, published a note about animal char- 

 coal, showing that it blanched vinegars and wines with much more energy than vege- 

 table charcoal; and lastly, in 1812, M. Derosnes proposed to employ animal charcoal, 

 in the purification of syrups and sugar-refining. The quantities of bone-black left in 

 the retorts employed by MM. Payen, for producing crude carbonate of ammonia, 



