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resisted cupellation, and which have afterwards been se-parated by other processes. An instance of this has beenalready mentioned in the ninth section, and a more re-markable one is given by Homberg in the memoirs ofthe French academy for 1693 - a quantity of gold, aftercupellation, quartation, fusion with antimony and thedifflation of the antimonial metal, and repeated fusionswith nitre, continued quite brittle though of a highcolour : by treating it again with antimony and lead, andworking off the fuperadded metals on a cupel, it lost itscolour also, and became grey, but by further repetitions,of the fusion, both its colour and malleability were atlength restored.

Juncker reports from Borrichius and Osiander, that ongrinding for a length of time, in a glass mortar, anamalgam of one part of gold and four of mercury, withdistilled water, there separates daily a black matter,which may be collected by pouring off the water andsuffering it to settle : that after the triture has been con-tinued for some weeks, the water yields, on being evapo-rated, some granules of a crystalline fait: that the blackpowder yields, on fusion, a green glass; and that the metalis thus resolved or destroyed. But mercury alone by con-tinued triture or agitation, is changed into a similarpowder, of which a part abides fixt in a considerablystrong fire : the vitresication probably proceeded fromsome particles abraded from the glass mortar; and thesaline matter, the proportion of which is acknowledgedto have been very minute, either præexisted in the wateror was extracted from the glass. Borrichius himselfaffords a strong presumtion that the black powder pro-ceeds rather from the mercury than from the gold :after some days, he observes, the amalgam grows stiff,and the separation more sparing, and therefore fresh mer-

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