Note 60 — PLATINUM, OR PLATINA.

From ſome late experiments made upon platina by the Count de Sikengen, and publiſhed in German by profeſſor Succow, it appears that the ſpecific gravity of pure platina is 21,000. When perfectly pure and in its metallic ſtate it was not calcined by deflagration with nitre, it did not admit of being hardened or ſoftened by tempering, like ſteel or other metals; it was drawn into a wire ¹⁄₁₉₄₀ of a line in diameter; this wire admitted of being flattened, and had more ſtrength than a wire of gold or ſilver of the ſame ſize. This platina is not fuſible by the ſtrongeſt fire, but melts in the focus of a burning glaſs; its colour white, ſhining like fine ſilver.

From conſidering the very intereſting experiments of the Count de Sikengen, I apprehend the following method to obtain pure and malleable platina will be found a good one.

Diſſolve the grains of native platina that are leaſt magnetic, in aqua regia. Precipitate the iron by means of phlogiſticated fixed alkaly. Then precipitate whatever elſe will fall, by cauſtic vegetable alkaly. Saturate the liquor with cauſtic foſſil alkaly, and ſet it by to chryſtallize. The yellow chryſtals thus obtained are to be hammered together at a welding heat, and the metallic parts will unite. W.