CHAP. 32.—QUICKSILVER.
There is a mineral also found in these veins of silver, which yields a humour that is always[963] liquid, and is known as “quicksilver.”[964] It acts as a poison[965] upon everything, and pierces vessels even, making its way through them by the agency of its malignant properties.[966] All substances float upon the surface of quicksilver, with the exception of gold,[967] this being the only substance that it attracts to itself.[968] Hence it is, that it is such an excellent refiner of gold; for, on being briskly shaken in an earthen vessel with gold, it rejects all the impurities that are mixed with it. When once it has thus expelled these superfluities, there is nothing to do but to separate it from the gold; to effect which, it is poured out upon skins that have been well tawed, and so, exuding through them like a sort of perspiration, it leaves the gold in a state of purity behind.[969]
Hence it is, too, that when copper has to be gilded,[970] a coat of quicksilver is laid beneath the gold leaf, which it retains in its place with the greatest tenacity: in cases, however, where the leaf is single, or very thin, the presence of the quicksilver is detected by the paleness of the colour.[971] For this reason, persons, when meditating a piece of fraud, have been in the habit of substituting glair of egg for quicksilver, and then laying upon it a coat of hydrargyros, a substance of which we shall make further mention in the appropriate place.[972] Generally speaking, quicksilver has not been found in any large quantities.
CHAP. 33.—STIMMI, STIBI, ALABASTRUM, LARBASIS, OR PLATYOPHTHALMON.
In the same mines in which silver is found, there is also found a substance which, properly speaking, may be called a stone made of concrete froth.[973] It is white and shining, without being transparent, and has the several names of stimmi, stibi, alabastrum,[974] and larbasis. There are two kinds of it, the male and the female.[975] The latter kind is the more approved of, the male[976] stimmi being more uneven, rougher to the touch, less ponderous, not so radiant, and more gritty. The female kind, on the other hand, is bright and friable, and separates in laminæ, and not in globules.[977]
CHAP. 34.—SEVEN REMEDIES DERIVED PROM STIMMI.
Stimmi is possessed of certain astringent and refrigerative properties, its principal use, in medicine, being for the eyes. Hence it is that most persons call it “platyophthalmon,”[978] it being extensively employed in the calliblepharic[979] preparations of females, for the purpose of dilating the eyes. It acts also as a check upon fluxes of the eyes and ulcerations of those organs; being used, as a powder, with pounded frankincense and gum. It has the property, too, of arresting discharges of blood from the brain; and, sprinkled in the form of a powder, it is extremely efficacious for the cure of recent wounds and bites of dogs which have been some time inflicted. For the cure of burns it is remarkably good, mixed with grease, litharge,[980] ceruse, and wax.
The method of preparing it, is to burn it, enclosed in a coat of cow-dung, in a furnace; which done, it is quenched with woman’s milk, and pounded with rain-water in a mortar.[981] While this is doing, the thick and turbid part is poured off from time to time into a copper vessel, and purified with nitre.[982] The lees of it, which are rejected, are recognized by their being full of lead and falling to the bottom. The vessel into which the turbid part has been poured off, is then covered with a linen cloth and left untouched for a night; the portion that lies upon the surface being poured off the following day, or else removed with a sponge. The part that has fallen to the bottom of the vessel is regarded as the choicest[983] part, and is left, covered with a linen cloth, to dry in the sun, but not to become parched. This done, it is again pounded in a mortar, and then divided into tablets. But the main thing of all is, to observe such a degree of nicety in heating it, as not to let it become lead.[984] Some persons, when preparing it on the fire, use grease[985] instead of dung. Others, again, bruise it in water and then pass it through a triple strainer of linen cloth; after which, they reject the lees, and pour off the remainder of the liquid, collecting all that is deposited at the bottom, and using it as an ingredient in plasters and eye-salves.