62 Mr. Ross on the Carburet of 'Nickel. [July, 



remarks which I had made upon this subject were submitted to 

 the Cambridge Philosophical Society soon after the fragment of 

 Mr. Belzoni's Egyptian Soros arrived in Cambridge. Since that 

 communication was made, having been occupied in the exami- 

 nation of some minerals that were brought by Humboldt from the 

 Andes, I found one that had been labelled " Quartz passing 

 into onyx." Externally it resembled Cryolite so much as to 

 deceive a very eminent mineralogist. It had been found upon 

 Chimboraqo in the kingdom of Quito at an elevation of 17,U00 

 feet above the level of the sea. It is barely hard enough to 

 scratch °lass ; but. its lively effervescence in acids, added to its 

 character before the blowpipe, soon made me acquainted with 

 its real nature. It is in fact a very curious sub-variety of arra- 

 gonite ; and it has the unusual property of assuming, first, a 

 black, and afterwards an ochreous yellow colour, before the 

 blowpipe, owing to a portion of iron which it contains. The 

 specific gravity also of this mineral from Chimborac.0 is 2*7. As 

 it differs from all the other sub-varieties of the hard carbonate of 

 lime in the change of colour which it sustains by the action of 

 heat, we may venture to give it a name, founded on its locality, 

 and call it Ctiiuiboracile, although, perhaps, it may be some time 

 before any additional specimens of it can be procured. 



Edward Danill Clarke. 



Article XI. 



On the Carburet of Nickel. By Mr. William Ross. 



(To the Editor of the Annals of Philosophy.) 



fclR, Manchester, June 8, 1813. 



About a year ago, being desirous of obtaining a specimen of 

 pure nickel, 1 prepared some or the oxide from the impure nickel 

 of the shops, following pretty nearly the process given by Dr. 

 Thomson in the first volume of the fifth edition of his System of 

 Chemistry, p. 391. The oxide I mixed with a small quantity of 

 powdered resin, and made it into a paste with oil; it was intro- 

 duced into a charcoal crucible, which was placed in sand in an 

 earthen one ; to this a cover was adapted, and secured by a lute 

 of pipe-clay and sand. In a day or two, when the luting had 

 become dry, the crucible with its contents was placed in a 

 powerful forge, and exposed to the most violent heat I could 

 raise for about three-quarters of an hour. By this process, I 

 expected to have a compact bright button of nickel : however, 

 I only obtained a piece of imperfectly fused metal, having the 

 aspect of plumbago, and soiling the fingers precisely as that 

 substance does. 1 was desirous to get rid of this plumbago-like 



