Experiments on the Fufion of Platina. 475 



the time of the continuance of the crucible in 

 the fire was computed from the time it began 

 to be red-hot until the laft charge of cauk. 



By feveral experiments made fince the above, 

 I have found that platina is capable of begin- 

 ning to melt fo as to form a fmooth furface in 

 136° and to be in perfect fufion at 150°. 



I tried the malleability of the mafs fufed in 

 experiment fifth, and with a moderate blow 

 with the hammer very little impreffion was 

 made, but with a few heavier flrokes, it broke 

 into two pieces. The grain was clofe and 

 refembled that of fradured fteel, but fomewhat 

 duller. I treated in the fame manner the mafs 

 melted per fe in experiment fixth, and with the 

 fame efFedt, and the grain was perfeftly fimilar. 

 On filing this latter piece, it was found very 

 hard, and exhibited a fplendour nearly as bright 

 as filver. 



EXPERIMENT X. 



Mr. Nowell, who was prefent at many of the 

 operations, defired me to try whether platina 

 would not melt on a bed of powdered clay or 

 bone a(hes. I filled a crucible about one fourth 

 part with calcined bone afhes in powder, and 

 put one ounce of platina wrapped up in paper 

 on it, and expofed it for two hours to the greateft 

 heat I could produce; but the platina was not 

 melted, only a cohefion had taken place. Part 

 of the bone ^fhes near the platina at the top, 



was 



