BY COMPRESSIOH. 12^3 



'lav. Tbe barrel, when opened, was found full of metal, and 

 ■the cradle being laid flat on the table, a considerable quantity 

 of metal ran from it, which had undoubtedly been lodged in 

 the vacuity of the large tube. When cold, I found that vacuity 

 still empty, with a plating of metal. The tube was very clean 

 to appearance,, and, when shaken, its contents were heard to 

 rattle. Abov^ the little tube, and the -cylinder of chalk, I 

 had put som« borax and sand, with a little pure borax in the 

 jniddle, and chalk over it. The metal had not penetrated be- 

 yond the borax and sand, by a good fortune peculiar to 

 ■this experiment; the intrusion of metal in this mode of exe- 

 cution, being extremely trosublesome. The button of chalk, 

 was found in a state of clean while carbonate, and pretty hard, 

 but without transparency. The little tube was perfectly clean. 

 Its weight -with its contents, seemed to have suffered no change 

 from what i-t had been whejj first introduced. Attending, 

 liowever, to the balance with scrupulous nicety, a small pre- 

 ponderance did appear on the side of the weight. This was 

 done away by the addition of the hundredth of a grain to the 

 •scale in which the carbonate lay, and an addition of anotlicr 

 ■hundredth produced in it a decided preponderance. Perhaps, 

 ■had the tube, before its introduction, been examined with the 

 •same care, as great a diftcrence might have been detected ; 

 ■and it seems as if there had been no loss, tit least not more 

 Ihan one-hundredth of a grain, which on 10.95 grains, amount 

 ■to 0.0912, say O.i per cent. <Thc carbonate was loose in the 

 little tube, and fell out bys-haking. It had a yellow colour, 

 and compact appearance, with a stony hardness under the 

 inife, and a stony fracture ; but with very slight facettes, 

 and little or no trans])arency.. In some parts of the specimen, 

 a whitish colour seemed to indicate partial calcination. On 

 examining the fracture, 1 perceived, with the magnifier, a 

 small globule of me-tal, not visible to the naked eye, quite in- 

 sulated and single. Possibly the substance may have con- 

 tained others of the same sort, which may have compensated 

 for a small loss, but there could not be many such, from the 

 general clean appearance of the whole. In the fracture, I saw 

 here and there small round holes, seeming, though imperfectly, 

 to indicate a beginning of ebullition. 



I made a number of axperiments in the same manner, that Mr-thofl of ope 



112 



rating with the 

 tuouth of tlie 



