I 4-93 )

tina weighed three hundred and ten grains, and conse-quently had lost above a third : it still resembled crude pla-tina, and retained its lustre; the brownish rusty coat, withwhich mine appeared covered after the first cementations,having probably been here rubbed oft'in the grinding. Thenitre was totally decomposed, and had acquired all thecharacters of alcalicity. The crucible and its support weretinged almost throughout of an amethyst colour, as usuallyhappens in the calcination of manganese with nitre.

The platina was treated in the same manner with threeOunces of fresh nitre. The crucible and its support werestill tinged of a fine amethyst colour, the nitre was to-tally alcali^ed, and all other circumstances happened as inthe first operation, except that the lighter parts, firstwashed oft, weighed only sixty grains: by calcination theybecame, as before, of a pitchy blackness: the remainingpowdery matter was of a clear grey, and weighed fortyfive grains: the platina, still bright, weighed two hundredand fifteen grains, or less than half of its first weight.

The operation was repeated with three ounces more ofnitre. The crucible and its support were now less stronglytinged. The first washings gave two grains of a lightpowder, in appearance much resembling the Eckertsbergblue earth; and by rubbing the rest of the platina inwater, there were obtained forty grains of a light powderof a grey-brown colour. The platina lost in this operationbut five grains; and so inconsiderable a diminution givinglittle hopes of any further effect from a repetition of theprocess, the experiment was here dropt.

It had been affirmed, that platina is a compound of goldand some other matter, so intimately combined together,as not to be separable without other methods of procedurethan are commonly practised or known. An adept, inthe pretended art of this higher metallurgic analysis,

Sffa boasted