If we could destroy metals, and again educe them destroyed from power to act, surely they would not be so porous. And as a child without correction is unapt to any goodness, but corrected is endued with all kind of vertue and learning, so also we must understand of metals which left in their natural state, namely drawn out of the earth without correction and emendation remain volatile, but corrupted and regenerated are made more noble, even as our bodies destroyed and corrupted, at length shall arise clarified before they come into Gods sight. Well said _Paracelsus_, that if in one hour metals were destroyed an hundred times, yet they could not be without a body, reassuming a new species and indeed a better, for it is rightly said, _Unius corruptio, alterius generatio_; for the mortification of a superfluous sulphureous body is the regeneration of the Mercurial soul, for without a destruction of metals perfection cannot be; therefore metals are to be destroyed and made formless, that thereby the superfluous earthy combustible sulphur being separated, the pure fine Mercurial species may spring forth. Of which thing more, when we Speak of Artificial stones. _Of the smoothing and polishing of looking-glasses_ A looking-glass, though it be very exactly melted and proportioned, yet is of no value if not rightly polished and smoothed; for easily in the smoothing any part it may suffer some dammage hurtful to it, and it is necessary to take from them first, the grosser part by the wheel, as the custom is with Pewterers and Copper-smiths with a sandy stone, then to apply to them a finer stone with water, until they are sufficiently smoothed by grinding; which done, the looking glasses are again to be taken from the wheel and to be moved to the small wooden wheel covered with leather, rubbed over with a fine prepared glazing stone until the crevises contracted in the turning no more appear, having got a cross line, afterward another small wheel covered with leather is required, to which a bloodstone prepared and washt with the ashes of tin rubbed on, to which likewise by the aforesaid means, according to the same line, the looking-glasses are so long to be moved till they get a sufficient fineness and brightness. You must keep such looking-glasses from the moist air, and breathing, and to wipe them when infected with air and breathing not with any woolen or linnen cloth, but with a Goats or Harts skin, and not any way, but according to the cross line, with which the looking-glasses are smoothed. They may also be smoothed by lead artificially melted, by first rubing them with a smiris and water, and then with a finer smiris and lead; lastly with a blood stone and ashes of tin: likewise also with whetstones, by changing for a finer every time, whence at length also they acquire a splendour by the ashes of tin.