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distilled off, there remains in the retort a saline mass,containing the gold; that on every fresh solution anddistillation with the same kind of aqua regia, the matterincreases more and more in its weight, and looks like afoul dark brown salt very hard of fusion ; that the liquorwhich distils is clear as water, and that nothing of thegold sublimes. He observes also, that an aqua regia madewith nitre in substance and the acid spirit of sea salt, andwith sea salt in substance and the acid os nitre, have lesseffect in volatilizing gold than that with rough sal ammo-niac above mentioned.

Though many have expected, from this volatilizationof gold, a resolution of it into dissimilar parts, it is notfound to have suffered any real change. If the distilledliquor, or the crystals, or the sublimate, be exposed toa heat gradually increased, the acid rises, without carryingwith it any part of the metal, the gold being left entirebehind. The menstruum is less disposed to elevate thegold a second time, than it was at first.

VI. Separation of goldfrom acids by inflammable liquors.

The very subtile inflammable fluid, obtained from amixture of vitriolic acid with vinous spirits, commonlycalled æther, or æthereal spirit of wine, poured into asolution of gold made in aqua regia or in spirit of salt,floats distinct upon the surface, being far lighter than theacid liquor and not at all miscible with it. The æther,os itself colourless, quickly becomes yellow, and the acidunderneath loses proportionably of its yellowness ; theæther imbibing the gold, keeping it permanently dis-solved, and, when loaded with the ponderous metal, con-tinuing still to float upon the acid. Gold is the only one,of the known metals, which the æther takes up fromacids, and hence this fluid affords a ready method of

distin-