In the same manner you may proceed with iron and steel, and there will remain behind a good crocus of a great stipticity or astringency, especially out of iron or steel, and may with good success be mixed with oyntments and plaisters. _Of Tin and Lead._ If Tin or Lead be dissolved therein, after the abstracting of part of the spirit, they will shoot into clear and sweet crystals. But Tin is not so easily dissolved as Lead; both may safely be used for medicines. Also there may be Spirits and flores got out of them by distilling. The rehearsing of the Preparation is needless, for what for the preparing of silver hath been taught, is to be understood also of other metals. _The use of the Crystals of Lead and Tin._ The Crystals of Lead are admirably good to be used in the plague for to provoke sweating and expel the venome out of the body; they may also with credit be used in the bloody flux. Externally dissolved in water, and clothes dipt therein and applied, they excellently cool and quench all inflammations, in what part of the body soever they do befal. Likewise the spirit thereof used _per se_ (and the flores mixed among oyntments) do their part sufficiently. But the crystals of Tin do not prove altogether so quick in operation, though they do act their part also, and they are more pleasant than those that are made of Lead; for in Tin there is found a pure sulphur of gold; but in Lead a white sulphur of silver, as is proved in my _Treatise of the generation and nature of Metals_. _Of Mercury._ When you dissolve common Mercury in rectified spirit of Nitre, and abstract the spirit from it again, then there will remain behind a fair red glistering precipitate; but when the spirit is not rectified, it will not be so fair, because that the impurity of the spirit remains with the Mercury and pollutes it. This calcinated Mercury is called by some _Mercurius præcipitatus_, and by others _Turbith minerale_, wherewith the Surgeons, and sometimes other unskilful Physicians do cure the Pox; they give at once 6, 8, 10. grains, (more or less) according to its preparation and force in operation to the patient; for if the spirit be not too much abstracted from it, it worketh much stronger, than when by a strong fire it is quite separated from it; for the spirits that remain with the Mercury make it quick and active, which else without the spirits would not be such.