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repeated fusion and frequent nealing,it became a little softerand tougher, so as to be drawn into pretty fine wire; but thecolour was still exceeding dull, more resembling that ofvery bad copper than of gold.

It appears from these experiments, that platina dimi-nishes the malleability of gold much less than it does thatof the other malleable metals; and infinitely less than lead,tin, iron, and the brittle metals do that of gold: that inconsiderable proportions it debases the colour of gold farmore than the usual alloy, communicating a peculiar andremarkable ill colour; and that it both hardens, and de-bases the colour of standard gold, with copper alloy, muchmore than fine gold: that in small proportions, as oneforty-feventh and downwards, it does not sensibly injureeither the colour or malleability of gold; and consequently,that large proportions of platina mixed with gold are dis-coverable at sight, but that small proportions, if perfectlyunited with the gold, will not betray themselves either tothe eye or in the workmans hands.

X. Plasma with Copper.

1. Equal parts of platina and copper, exposed, with-out addition, to a strong fire hastily excited by bellows,soon became fluid, but not thin; and lost about one sixty -fourth. The metal proved extremely hard to the file,broke difficultly on the anvil, flew asunder upon endea-vouring to cut it with a chisel, and appeared internally ofa coarse grained texture and white colour.

2. One ounce of platina and two of copper, urged witha quick fire in a blast furnace, without addition, flowedsufficiently thin, and scarcely suffered any loss. The me-tal was still very hard, and stretched but little under thehammer. It looked darker coloured than the foregoing,with a flight reddish cast.

3. One