i 3 8 EFFECT'S of HEAT 



On the 25th, in a fimilar experiment, a heat of 64 was ap- 

 plied, without any water within the barrel. The platina tube, 

 (having been contaminated in a former experiment with fome 

 fufibie metal), melted, and the carbonate retaining its cylin- 

 drical fhape, had fallen through it, fo 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 fulphur. The carbonate itfelf was very 

 tranfparent, refembling a piece of fnow in the act of melting. 



On the 26th of June, I made an experiment with this car- 

 bonate, which afforded a beautiful refult. One grain of wa- 

 ter was introduced with great care ; yet there was a lofs of 

 6.5 per cent., and the refult has fallen to decay. The pyro- 

 meter indicated 43 . On the outfide of the platina cylinder, 

 and on one of the lids, were feen a fet of globules, like pearls, 

 as once before obtained, denoting perfect fufion. When the 

 upper lid was removed, the fubflance was found to have funk 

 almoft out of light, and had afiumed a form not ealily defcri- 

 bed. (I have endeavoured to reprefent it in fig. 31. by an ideal 

 fection of the platina- tube and its contents, made through the 

 axis of the cylinder). The powder, firfl fhrinking upon itfelf 

 in the ad of agglutination, had formed a cylindrical rod, a 

 remnant of which {a h c) flood up in the middle of the tube. 

 By the continued action of heat, the fummit of the rod (at a) 

 had been rounded in fufion, and the mafs being now fof- 

 tened, had funk by its weight, and fpread below, fo as to 

 mould itfelf in the tube, and fill its lower part completely 

 (dfge). At the fame time, the vifcid fluid adhering to the 

 fides (at e artd d), while the middle part was finking, had 

 been in part left behind, and in part drawn out into, a thin 

 but tapering fhape, united by a curved furface (at b and c) ta 

 the middle rod. When the platina tube was unwrapt, the 

 thin edges (at e and d) were preferved all round, and in a 



Hate 



