No More Learning

(9) In           of medicines I do find strange, specially considering
how mineral medicines have been extolled, and that they are safer for the
outward than inward parts, that no man hath sought to make an imitation
by art of natural baths and medicinable fountains: which nevertheless are
confessed to receive their virtues from minerals; and not so only, but
discerned and distinguished from what particular mineral they receive
tincture, as sulphur, vitriol, steel, or the like; which nature, if it
may be reduced to compositions of art, both the variety of them will be
increased, and the temper of them will be more commanded.