Experiments on the Fufion of Platlna. 47 1 



tools : it is not highly polilhed, and is much paler 

 th^n fteel, but not fo white as filver. 



EXPERIMENT V. 



I mixed one ounce of platina in grains with one 

 drachm of alkali of tartar, two drachms of borax 

 powder, and one drachm of charcoal powder, and 

 put the mixture on a bed of charcoal duft in the 

 crucible j and as I had obferyed fomething of an 

 incipient fufion when the crucible had been in 

 the fire rather more than half an hour, I expofed 

 it one hour and a half, and obtained a perfed 

 fufion. The fufed mafs was in two parts. The 

 deficiency of weight of platina thus fufed was 

 half a drachm. I did not preferve the whole of 

 the charcoal, but obtained from what was faved 

 near twenty grains of unfufed platina, which I 

 fuppofed were difperfed too far from the power 

 of the fire to be melted. The fpecific gravity of 

 this parcel of fufed platina was 16.8. 



EXPERIMENT VI. 



I wrapped up one ounce of platina in a piece 

 of white paper to prevent any difperfion of its 

 particles, and placed it on a bed of charcoal, 

 covering alfo the paper with charcoal pow- 

 der, and in two hours obtained a perfed fufion, 

 with the lofs of only a few grains of the metal. 

 The fpecific gravity of this melted platina was 

 15.704. The difi^erence of fpecific gravity 

 H h 4 between 



