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gold. It corrodes the skin, making it harsh and rough,but I have not observed that it gives any stain, not eventhe yellow one which the menstruum by itself communi-cates to the skin. Ivory, feathers, silk, wood, and linen,were dipt in the diluted liquor and exposed to the sun, andthe dipping and drying repeated three or four times : theyall became brown, from the colouring matter of the solu-tion having dried upon the surface; but water washed itoff readily, and left them colourless as at first, except thatthe silk retained a slight brownishness after the washing.The solution dropt upon warm marble, immediately cor-roded it, but without giving any colour.. Dropt into infu-sions of cochineal, it did not heighten but destroy the redor purplish colour, and changed them to a brownish orblackish : some of the mixtures applied on paper with apencil, appeared nearly of the same hue with Indian ink inits paler shades.

II. Crystallization of Plasma.

Solutions of platina crystallize much more easily thanthose of gold. As a considerable heat is necessary formaking the aqua regia saturate itself with the metal, thesatiated solution generally deposites, by the time it is growncold, a brownish red sediment, which is no other than anumber of minute crystals. A quantity of the solutionhaving been set by in an open glass, in warm weather, thesuperfluous moisture gradually exhaling left moderatelylarge crystals, of a dark almost opake red colour, of irre-gular figures, variously joined together, most of them inform of leaves, like flowers of benzoin but thicker. Theirtaste was nauseous and somewhat sharp, but not near socorrosive as might be expected from the great quantity ofnitrous and marine acids combined with the metal. Washedwith proof spirit, they became somewhat paler, but still

remained;