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perficially with the gold, it may nevertheless, when com-bined more intimately by fusion, elude this method oftrial. Mixtures of gold with small proportions of platinawere therefore kept in fusion for several hours,with a verystrong fire, and afterwards dissolved in aqua regia. Thesolutions were diluted considerably with water, and a so-lution of pure fixt alcaline salt gradually added, so long asany effervescence or turbidness ensued. The liquors provedpaler than when the two metals had been dissolved sepa-rately, but retained colour enough to betray the platina.As the degree of colour was not here so great, as mighthave been expected from the quantity of platina whichthere was reason to believe they contained, I tried to dis-cover the platina in them by some character more con-spicuous. I put into the filtered liquors some plates ofpure tin: the tin presently contracted an olive hue, andthrew down a large quantity of brownish precipitate, as itdoes from the common solutions of platina: it was observa-ble, that the tin plates were often sensibly acted upon evenwhile the liquor was overcharged with alcali.

It has been further suggested, that since a part of platinais precipitated as well as gold by fixt alcaline salts, if onlythis part be mixed with gold, it will elude this trial, andbe thrown down by alcalies again, along with the gold,from the solution of the compound. To determine thispoint, I melted with gold a precipitate of platina madeby fixt alcali, and kept them in strong fusion for an hourand a half: they seemed to unite more easily than golddoes with the crude platina, and formed a smooth neatbead,which hammered pretty well into a thin plate beforeit cracked, and appeared internally uniform and equal.This compound being dissolved in aqua regia, the solutiondiluted with a little water, and a solution of fixt alcalinesalt added by degrees till the acid was more than saturated,

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