CARBON. 361 



ized, it does not crackle and fly. For black crayons, willow affords 

 the best charcoal, it being uniformly soft. Ivory black is the coal of 

 ignited ivory prepared in close vessels ; the common ivory black is 

 often made from bones. 



(hh.) The durability of charcoal is seen in the figures on the dial 

 plates of steeples, which often stand out in bold relief, while the rest of 

 the wood, painted white, is worn away. 



(ii.) Lampblack, ignited in a crucible, and cooled before it is un- 

 covered, and the charcoal which Is procured by passing the vapor of 

 oils or of alcohol through ignited tubes, is the purest carbon that 

 art can prepare. It is an impalpable black powder, and more than 

 twice as heavy as water.* 



(jj.) Bistre, a beautiful brown pigment, is prepared from an 

 aqueous infusion of wood soot. 



(kk.) Animal charcoal is more dense and less combustible than ve- 

 getable, and contains phosphate of iron ; it is distinguished from ve- 

 getable, as the latter burns on an ignited iron into white ashes, form- 

 ing a bitterish liquor with sulphuric acid, but the residuum of animal 

 matter is much less soluble, and forms a compound having a very dif- 

 ferent taste. f 



(II.) Charcoal is very effectual in depriving treacle or molasses of 

 its peculiar taste ; twenty four pounds, diluted with an equal weight 

 of water, and boiled for half an hour with six pounds of pulverized 

 charcoal, were entirely deprived of the empyreumatic taste and smell, 

 and being strained and evaporated to a proper consistence, had the 

 flavor of good sugar. { Honey may be treated in the same manner, 

 and with the same effect.^ 



(mm.) The due preparation of charcoal is of the last consequence 

 to success in these operations. Common charcoal is almost inert ; it 

 is indispensable that it be fresh made ; or re-ignited, and that it be 

 secluded from the air till it is used. 



(nn.) Charcoal is used in polishing brass and copperplates and 

 lanthorn leaves ; in tracing the outlines of drawings, and in giving 

 some peculiar tints to glasses colored in imitation of the gems.|| 



(oo.) The ancients knew that charcoal will not decay. The piles 

 driven, more than than two thousand years ago, in founding the tem- 

 ple of Ephesus, were charred, and those that support the houses 



* Davy's Elements, p. 299. A very pure charcoal is prepared also from sugar 

 and starch. 



t Parkes' Essays, Vol. I, p. 414. 



t Charcoal has been applied to the refining of sugar, and a patent was taken out 

 for it some years ago in London. Mr. Parkes says, that finer loaves of sugar than 

 were manufactured at any other establishment in London, were as he supposes, pro- 

 duced in this manner. 



Parkes' Essays, Vol. I, p. 419. || Parkes. 



46 



