47 8 Experiments on the Fufton of Platina. 



a complete fufion. I repeated this experiment 

 two or three times, and always fufed the platina, 

 fo that I think it extremely probable, that in 

 the three operations I made to fufe Dr. Pearfon's 

 platina and failed, there was too much charcoal 

 added at the bottom of the crucible. 



I have alfo obferved in' one of my experiments 

 for fufing platina by itfelf, that it continued in a 

 fluid ftate for more than five minutes after the 

 crucible was taken from the fire, for on breaking 

 the crucible, it was perfectly fluid and ran like 

 melted lead on the floor of the laboratory. 



I tried to melt another parcel of platina in 

 grains fent to me by Dr. Pearfon, but the cru- 

 cible falling from the fl:and after it had been in 

 the fire half an hour, there was only an adhe- 

 fion. This adhefive mafs was bruifed and 

 treated as in the laft experiment, and it melted 

 in two hours. Its fpecific gravity was 14.65, 

 but there were feveral cavities found in it when 

 broken, and it was the whiteft of any of my 

 fpecimens. 



EXPERIMENT XV. 



As all the experiments made by me were done 

 in one furnace, and the degrees of fire em- 

 ployed very little above 160'' of Wedgwood's 

 pyrometer, I tried to melt fome platina perfe in 

 another furnace, which produced a confider- 

 ably greater degree of heat. In my firft experi- 

 ment 



