Experiments on the Fujion of Platina. 477 



EXPERIMENT XIII. 



The other three parts of the precipitate pre- 

 pared in the lafl: experiment, were treated in the 

 fame manner with dry volatile alkali, and I 

 endeavoured to melt it upon a bed of charcoal, 

 but could only obtain fmall globules after the 

 application of an intenfe heat for two hours. 

 Thefe globules were powdered and mixed with 

 one drachm of borax, one drachm of alkali of 

 tartar, and one drachm of charcoal: a very fmall 

 quantity of charcoal powder was at the bottom of 

 the crucible, and in two hours I obtained a com- 

 plete fufion. There was one large button, which 

 weighed one hundred and fixty grains, and 

 feveral fmall globules, fome of which were fo 

 intermixed with the vitreous flux that they 

 could nor be weighed. The fpecific gravity of 

 this was 23.4, it was very clofe grained and 

 had no cavity, but was not malleable. 



EXPERIMENT XIV. 



As I had melted the platina in the lafl ex- 

 periment with a flux and only a little charcoal at 

 the bottom of the crucible, I tried to melt it 

 without any flux, but with only a fmall quantity 

 of charcoal. The platina was wrapped in paper 

 and juji covered with charcoal^ and (as in all the 

 former experiments) an inverted crucible ferved 

 inftead of a cover. In two hours time I obtained 



a complete 



