CARBON. 359 



(j.) Plunged into mercury, or merely resting on it, it absorbs 

 much of that metal into its pores. 



(k.) Heated in contact with common air, it burns away entirely ; 

 very rapidly r , and wholly, if immersed in oxygen gas in sufficient 

 quantity. A piece of charred bark burns best, and with lively scin- 

 tillations. 



(/.) Sulphuric acid boiled on charcoal powder is decomposed, and 

 sulphurous acid gas is liberated. 



(m.) The decomposition of the sulphates by charcoal, is a striking 

 instance of its action on sulphuric acid. 



(n.) To prepare charcoal for clarification; take that which is well 

 burned, pulverize and sift it ; heat it strongly away from the air, as 

 in a crucible with a small hole in the cover, or covered with sand ; 

 it must then be bottled tight, till it is wanted. 



(0.) Tincture of alkanet, diluted with water, mixed with well pre- 

 pared charcoal, and simmered over the fire, and then thrown upon a fil- 

 ter, comes through perfectly limpid. Mixed with common vinegar or 

 wine, a thick froth rises, and the liquors are clear after filtration. It 

 is sometimes necessary to boil the vinegar upon the charcoal. 



(p.) Ditch, sink, or puddle water, or even that of a surgeon's tub 

 is thus rendered limpid, inodorous, and insipid ; and rancid oils are 

 restored by repeated filtration through charcoal. 



(q.) The prepared charcoal is an excellent dentifrice ; that from 

 the shell of the cocoa nut is preferred ; the charcoal of the kernels 

 of nut fruit is very delicate, and that of carbonized wheat bread is 

 very good.* 



(r.) Solutions of impure acid of tartar, crude tartar, crude nitre, 

 and other salts are rendered colorless by being boiled with charcoal 

 powder, and are thus made to crystallize in snow white purity. 



(5.) Impure carbonate of ammonia, sublimed from an equal weight 

 of charcoal powder, is rendered white and deprived of its foetid 

 smell. Charcoal also destroys the heavy sickening odor arising from 

 oiled and gummed silks, such as those of which hat cases and um- 

 brella coverings are made, and it speedily removes any unpleasant 



porous ; it has no resemblance to charcoal ; sinks as readily in strong sulphuric 

 acid, as it before floated on water with its volume half out ; its gravity was there- 

 fore increased four times, compared with the charcoal in mass. 



This observation was first made by myself in March 1823, and has been repeat- 

 ed many times since ; with a powerful deflagrator, it constantly occurs. The sub- 

 stance resembles greatly, the residuum found in the iron gas bottles, and there 

 seems no reason to doubt that it proceeds from the volatilization and fusion of the 

 charcoal along with whatever foreign substances it may contain. The objections 

 of Prof. Vanuxem seem to have related to a different substance. Am. Jour. Vol. 

 IV, p. 371. 



* Soot is one of the very best dentifrices ; for, besides the carbon, there are the 

 detergent ammoniacal salts, and a bitter principle, and other active agents. 



