Sonje Experiments on the Comhislion of the Diamond. 493 



go no further din-rinution : two fragments remained, which, as it 

 was afterwards found, weighed -52 of a grain; the barometer 

 during the experiment was at 29-9 inches, the thermometer at 

 56^ Fahrenheit. When the original temperature of tlie globe 

 was restored, there was not the slightest appearance of vapour 

 or humidity; the interior was as clear as before the experiment, 

 and there was no solid matter of any kind separated in the tray. 

 The fragments of diamond which remained were not black, but 

 had lost their lustre like glass that has been acted on by fluoric 

 acid, nor at any period of the process was any carbonaceous 

 appearance perceived upon them. When the communication 

 was made bv the stop-cock between the interior of the globe and 

 a surtace of mercury, a minute quantity entered equal to 1-5 

 grain onlv. 



A portion of the gas in the globe was transferred into a tube 

 in the mercurial apparatus, and the oxygen it contained ab- 

 sorbed l)y the combustion of phosjjhorus; 3-5 parts of gas 

 heated in this way Ifft a residuum of 2-5 parts. A portion cf 

 the gas was agitated with lime-water, when seven ]oarts out of 

 ten were absorbed. I exposed the gas which remained after 

 the combustion of phosphorus to several tests ; it had not only 

 the obvious characters of carbonic acid, but exhibited exactly 

 the same chemical phaenomena. Potassium strongly heated in 

 it in a small glass tube over mercury, burnt with a dull red light, 

 and formed an alkaline product of the same intense black co-' 

 lour as tliat ])roduced by its combustion in the carbonic acid 

 procured by the dissolution of marble : distilled water absorbed 

 rather less "than its own volume of the gas, and became snbacid, 

 sparkled by agitation, gained the taste and smell of a sblution of 

 carbonic acid in water, precipitated in the same manner lime- 

 water, and when in excess redissolved the precipitate. To as- 

 certain if this precipitate was exactly the same in composition as 

 pure carbonate of lime, I made a sufficient quantity of it by 

 pouring lime-water into the recipient containing the results 

 of the first experiment ; and after collecting and drying it at the 

 temperature of 2 1 2° Fahrenheit, I introduced a quantity of it 

 contained in some foil of platinum through mercury into a glass 

 tube filled with mercury, and I heated in the same manner an 

 equal quantity of finely' powdcied Carrara marble, and admitted 

 to them equal iiuantities of solution of muriatic acid. In this 

 trial, there was rather more clastic fluiil disengaged from the 

 Carrara marble than from the carl)onate of lime from the dia- 

 mond ; but on examining the foil of platinum after the experi- 

 ment, I found tliat a littfe of the carbonate had not been acted 

 upon: 1 tried two similar experiments, substituting bibulous 

 paper instead of the metallic foils for infolding the carbonates ; 

 Vol. 44. No. 200. Dec. 1814. E c the 



