i3 Ejftxts of Seat modified hy Compression. 



ment, seemed to have sustained a loss of 12 per cent, on 

 the original carbonate introduced. But, the substance sur- 

 rounding the fragment being inappreciable, it was \m possible 

 to learn what loss had been really sustained. Examining 

 the little tube, J found its edges clean, no boiling over hav- 

 ing taken place. The top of the small lump of chalk had 

 sunk much. When the little tube was broken, its contents 

 gave proof of fusion in some parts, and in others of the 

 nearest approach to it. A strong action of ebullition had 

 taken place all round, at the contact of the tube with the 

 carbonate : in the heart the substance had a transparent 

 granular texture, with little or no crystallization. I he small 

 piece of lumphchalk was united and blended with the ram- 

 med pov ; ier, so that they could scarcely be distinguished. 

 In the lower part of the carbonate, where the heat must have 

 been weaker, the rod had acted more feebly on the tube, 

 and was detached from it : here the substance was firm, and 

 was highly marked in the fracture with crystalline facettes. 

 Wherever the carbonate touched the tube, the two substances 

 exhibited, in their mixture, much greater proofs of fusion 

 than could be found in the pure carbonate. At one place, a 

 stream of this compound had penetrated a rent in the inner 

 tube, which it had tilled comp'etely, constituting a real vein, 

 like those of the mineral kingdom; which is still distinctly 

 to be seen in the specimen.- It had then spread itself upon 

 the outside of the inner tube to the extent of half an inch in 

 diameter, and had enveloped the fragment of porcelain al- 

 ready mentioned. When pieces of the compound were 

 thrown into nitric acid, some effervesced, and some not. 



I repeated this experiment on the same dav with two grains 

 of water. The furnace being previously hot, I continued 

 the fire during uu« half- hour with the muffle open, and an- 

 other with a cover upon it. I then let the barrel down by 

 means of the pul'ey. The appearance of a large longitudinal 

 rent made me at first conceive that the experiment was lost, 

 and the barrel destroyed :> the barrel was visibly swelled, and 

 in swelling had ourSt the cru.-it of smooth oxide with which 

 it was surrounded: at the same time no exudation of metal 

 had happeurd, and all was sound. The metals were thrown 



out 



