30 On the Use of Animal Charcoal as a Flux. [Jan. 



Article V, 



On the Use of Animal Charcoal as a Flux. 

 (To the Editors of the Annals of Philosophy-.) 



GENTLE.'^IEN, 



Th e great power of wood charcoal as a flux for minerals and 

 metaUic ores has been long known, and extensively taken 

 advantage of in the arts and operations of chemistry, but I am 

 not aware that any application of animal charcoal to the same 

 purposes has hitherto been attempted. The following facls, 

 however, it is thought, furnish sufficient grounds for believing 

 that the latter might prove an advantageous substitute for the 

 former, in those cases where its comparative expense would 

 admit of its employment; and they may, therefore, perhaps, 

 obtain a corner in the Annals of Philosophy if not occupied with 

 more important matter. 



Beino- in the habit of using animal charcoal as a dentrifice, I 

 nearly filled a brass crucible of moderate size, and about four- 

 tenths of an inch in thickness, with ivory-black, for the purpose 

 of purifying it by re-ignition. The crucible was closed with a 

 cast iron cover, which had a small perforation in it as a vent for 

 the cas which was extricated ; and in this state was set in the 

 fire-place of an air furnace, which was commonly employed for 

 heating alkaline lixivia. The fire was not very large, though 

 thoroughly inflamed, and the grate door was left wide open. 

 The crucible soon acquired a red heat (to which it had, prior to 

 this, been frequently exposed), and the gas burned steadily at 

 the aperture in the cover. Being obhged to leave it at this 

 period, on my return in about ten minutes, I was a little surprised 

 to find the iron cover of the crucible lying by itself, and no ves- 

 tige of the latter apparent in the fire-place. On examining the 

 ash-pit several rugged pieces of brass were found, and two large 

 masses of cinders, firmly compacted together by an upper coat- 

 ing of oxidized brass. In one of these a large stick of the metal 

 was imbedded, which broke with a rough coppery appearance, 

 but on filing immediately displayed its brassy nature. 



As the heat by which this was eflected appeared to me much 

 inferior to that which brass generally requires for its fusion, I 

 exposed some brass wire, about one-tenth of an inch in diame- 

 ter, by itself in the same fire, and closed the door. After 

 remaining there nearly half an hour, it was taken out broken 

 into two parts. It was become oxidized, and, as it were, worm- 

 eaten on its surface, and was rendered very brittle in its fracture, 

 but it had not the least appearance of any loss by fusion. 



Endeavouring again to effect my purpose with the ivory-black, 



