The celebrated M. de Jussieu having viewed the whole himself, in a journey he made to this mine, furnished us with this description of the work. PROCESS II. _To give Mercury, by the action of Fire, the appearance of a Metalline Calx._ Put Mercury into several little glass matrasses with long and narrow necks. Stop the matrasses with a little paper, to prevent any dirt from falling into them. Set them all in one sand-bath, so that they may be surrounded with sand as high as two thirds of their length. Apply the strongest degree of heat that Mercury can bear without subliming: continue this heat without interruption, till all the Mercury be turned to a red powder. The operation lasts about three months. _OBSERVATIONS._ Mercury treated according to the process here delivered hath all the appearance of a metalline calx, but it hath no more: for, if it be exposed to a pretty strong degree of fire, it sublimes, and is wholly reduced to running Mercury, without the addition of any other inflammable matter; which proves that during this long calcination it lost none of its phlogiston. The volatile nature of Mercury, which permits it not to bear a heat of any strength without subliming, prevents our examining all the effects that fire is capable of producing on it. Yet there is reason to believe that, as this metallic substance resembles the perfect metals in its weight, its splendour, and a brilliancy which resists all the impressions of the air without alteration, it would like them be unchangeable by the greatest force of fire, if it were fixed enough to bear it. In order to give Mercury the form of a metalline calx, it must necessarily be exposed for about three months together, to the utmost heat it can bear without subliming, as is above directed. Boerhaave kept it digesting in a less heat for fifteen years successively, both in open and in close vessels, without observing it to suffer the least change; except that there was formed upon its surface a small quantity of a black powder, which was reduced to running Mercury by trituration alone. Mercury thus converted to a red powder is known in chymistry and medicine by the name of _Mercury precipitated per se_: a title proper enough, as it is actually reduced to the form of a precipitate, and that without any additament; but very improper on the other hand, considering, that in reality this Mercury is not a precipitate, as not having been separated from any menstruum in which it was dissolved. PROCESS III. _To dissolve Mercury in the Vitriolic Acid. Turbith Mineral._ Put Mercury into a glass retort, and pour on it thrice its weight of good Oil of Vitriol. Set the retort in a sand-bath; fit on a recipient; warm the bath by degrees till the liquor just simmer. With this heat the Mercury will begin to dissolve. Continue the fire in this degree till all the Mercury be dissolved. _OBSERVATIONS._