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z. The platina, discoloured by the two foregoing ex-periments, was put into a crucible, which was covered,and kept for half an hour in a pretty strong pre, sufficientfor the melting of cast iron. The platina lost the ill co-lour which it had contracted in a weaker heat, and becamebrighter and whiter than it had been at first. The grainsstuck together, so as to come out of the crucible in onelump; but they readily fell asunder again on a flight blow,and did not appear to have at all melted, or altered theirshape,

4. Some of this brightened platina, kept in a moderatered heat for an hour, contracted a dark colour as before;and being afterwards urged hastily with a strong fire, itbecame again bright, almost like silver, I tried the mal-leability of several of the grains, both when discolouredand when brightened by fire, and found that in bothstates,, as in the crude mineral, some bore to be consider-ably extended, while others cracked or broke trom a blowor two of the hammer.

5. I proceeded to try the effect of greater degrees ofheat, having fitted up for this purpose a blast-furnace orforge with two pair of large bellows. An ounce of pla-tina, in a black-lead crucible, was urged in this furnacewith a sea-coal fire, for more than an hour. The heatwas so vehement, that the crucible in great part vitrefied;and the flip of Windsor brick which it was covered with,though defended by a thin coating of Sturbridge clay, asalso the internal parts of the furnace opposite to thebellowfes, melted and run down. The grains of platinaremained unmelted, being only superficially united into alump of the figure of the bottom of the crucible: theircolour was a good deal brighter and more silvery than at•first; and they seemed to cohere more firmly than thosewhich had undergone the weaker heat in No. 3.

6, The