The lead is calcined in thin plates, laid with sulphur in shallow vessels, the mixture being stirred with iron rods or stalks of fennel-giant, until the melted metal becomes calcined; when cold, it is pulverized. Some persons calcine lead-filings in a vessel of raw earth, which they leave in the furnace, until the earthenware is completely baked. Others, again, mix with it an equal quantity of ceruse or of barley, and triturate it in the way mentioned for raw lead; indeed, the lead which has been prepared this way is preferred to the spodium of Cyprus. CHAP. 51.—FIFTEEN REMEDIES DERIVED FROM THE SCORIA OF LEAD. The scoria[1736] of lead is also made use of; the best kind being that which approaches nearest to a yellow colour, without any vestiges of lead, or which has the appearance of sulphur without any terreous particles. It is broken into small pieces and washed in a mortar, until the mortar assumes a yellow colour; after which, it is poured off into a clean vessel, the process being repeated until it deposits a sediment, which is a substance of the greatest utility. It possesses the same properties as lead, but of a more active nature. How truly wonderful is the knowledge which we gain by experiment, when even the very dregs and foul residues of substances have in so many ways been tested by mankind! CHAP. 52.—SPODIUM OF LEAD. A spodium[1737] of lead is also prepared in the same manner as that extracted from Cyprian copper.[1738] It is washed with rain water, in linen of a loose texture, and the earthy parts are separated by pouring it off; after which it is sifted, and then pounded. Some prefer removing the fine powder with a feather, and then triturating it with aromatic wine. CHAP. 53.—MOLYBDÆNA: FIFTEEN REMEDIES. Molybdæna,[1739] which in another place I have called “galena,”[1740] is a mineral compounded of silver and lead. It is considered better in quality the nearer it approaches to a golden colour and the less lead it contains; it is also friable, and of moderate weight. When it is melted with oil, it acquires the colour of liver. It is found adhering also to the furnaces in which gold and silver have been smelted; and in this case it is called “metallic.” The most esteemed kind is that prepared at Zephyrium.[1741] Those kinds, too, are considered the best that are the least earthy and the least stony. It is used in preparing liparæ,[1742] as also for soothing or cooling ulcers, and as an ingredient in plasters, which are applied without ligatures, but are used only as a liniment for producing cicatrization on the bodies of delicate persons and the more tender parts. The composition is made of three pounds of molybdæna, one pound of wax, and three heminæ of oil; to which are added lees of olives, in the case of aged persons. Combined with scum of silver[1743] and scoria of lead, it is employed warm in fomentations for dysentery and tenesmus. CHAP. 54.—PSIMITHIUM, OR CERUSE; SIX REMEDIES.