[ 592 ] 
and incorporates with thefe Metals 5 rendering the 
Mixture, like itfelf, extremely hard and brittle. 
Having been melted in an Allay Furnace, on a Tell 
with Lead, and therewith expoled to a great Fire 
for three Hours, till all the Lead was wrought off, 
the Platina was afterwards found remaining at the 
Bottom of the Teh, without having fuffer'd any Al- 
teration or Diminution by this Operation. 
A Piece of Platina was put into ftrong and pure 
Aqua fortis , and therewith placed in a Sand-heat 
for twelve Hours: The ‘Platina , when taken out of 
the Aqua fortis, was found of the fame Weight as 
when put into ir; being in no-wife diffolved or cor- 
roded by that Menftruum. 
It had been reported, that this Semi-metal was 
fpecifically heavier than Gold j but having weigh'd 
fcveral Pieces of it hydrollatically in a nice A Hay- 
Balance, I found one of thefe Pieces to weigh in 
Air gr. and in Watery. -—- 2 . : So that its fpe- 
cific Gravity was to that of Water exactly as 15 : i_ 
Another Piece, that feem’d to be caft very open and 
porous, I found in Gravity to Water only as 13.91 
to 1. Altho' this laft mention’d Piece, could it have 
endur’d the Hammer as well as Gold, might proba- 
bly have been reduc’d to a confiderably greater De- 
gree of Solidity than that of the firft-meniion’d Spe- 
cimen. For the pureft Gold is feldom found, after 
Fufion, to come up to its true fpecific Weight, until 
it hath been brought up to its greateft Degree of 
Solidity under the Hammer. 
I alio weigh’d an equal Mixture of Gold and Pla- 
tina , which. I found nearly as ponderous as Gold 
itfelf 5 the fpecific Weight of this Mixture being to 
that of Water as 19 to 1. 
It 
