BY COMPRESSION. 119 



brittle state, though consistino- generally of clear and shiiiing 

 particles. I at last, however, succeeded in obtaining some 

 very good results with this carbonate. 



In an experiment made with it on the ISth of June, In a and in another 

 strong heat, I obtained a very firm mass with a saline frac- fuJ^^'^'"^*''^ 

 tare, moulded in several places on the platina, which was- 

 now used in the cylindrical form. On the 23d, in a similar 

 experiment, tlie barrel fouled, and the subject of experiment 

 was found in an entire state of froth, proving its former 

 fluidity. 



On the 2jth, in a similar experiment, a heat of 64° was Similar exi^eri- 

 applied without any water within the barrel. The platina 

 tube, (having been contaminated in a former experiment 

 with some fusible metal), melted, and the carbonate retain- 

 ing its cylindrical shape, had fallen through it, so as to 

 touch the piece of porcelain which had been placed next to 

 the platina tube. At the point of contact, the two had run 

 together, as a hot iron runs when touched by sulphur. The 

 carbonate itself was very transparent, resembling a piece of 

 snow in the act of melting. 



On the 26'th of Jane, I made an experiment with this car- Another expe- 



booate, which afforded a beautiful result. One grain of '""^"^."J'"^^ 



° perfect fusron. 



water was introduced with great care ,• yet tliere was a loss 



of 6.5 per cent., and the result has fallen to decay. The 

 pyrometer indicated 43°. On the outside of the platina cy- 

 linder, and on one of the lids, were seen a set of globules, 

 like pearls, as once before obtained, denoting perfect fusion. 

 When the upper lid was removed, the substance was found 

 to have sunk almost out of sight, and had assumed a form 

 not easily described. (I have endeavoured to represent it in 

 fig. 3i. by an ideal section of the platina tube and its con- 

 tents, iiAade through the axis of the cylinder). The powder, 

 first shrinking upon itself in the act of agglutination, had 

 formed a cylindrical rod, a remnant of which fa b cj stood 

 up in the middle of the tube. By the continued action of heat, 

 tlie summit of the rod (at a) had been rounded in fusion, and 

 the mass being now softened, had sunk by its weight, and 

 st{)rcad below, so as to mould itself in the tube, and fill its 

 lower part completely (dfg e). At the same time, the vis- 

 cid fluid adhering to the sides (at e and d), while the middle. , 



part 



