Know that the greatest part of medicinal waters in _Germany_, and other countries as well hot as cold carry with them from the earth a certain sulphureous acidity more or less: in which acidity consists that medicinal faculty and vertue of this or that water. And if those waters lose their odour and tast by the exhaling of their subtile spirits, then also they loose their vertues; although also there be found some waters, which have not only a spiritual sulphur, but also are impregnated with a certain mineral, or metallick body mixed with Allome, or Vitriol, which comes not elsewhere then from the common water running through the mines. There are found also other baths, the power and vertue whereof consists not in any spiritual sulphur, nor in any metallick body mixed with salt, but only in a certain spiritual salt mixed with a certain subtil fixed earth, which waters do not run through metallick mines as others do, but rather stones of the mountaines calcined with a subterraneal fire, whence also they borrow their subtil acidity with their insipid earth. And this no man will deny that hath the knowledge of volatile and fixed salts of minerals, and metals: the which I am able to demonstrate with very many, and most evident reasons, if time and occasion would permit; but it shall be done sometime or other as hath been said in a peculiar treatise. Now therefore I will only teach how by salts, minerals, and metals, artificial Baths may be made, which are not only not inferiour to the natural in vertue, but also oftentimes far better, and that without much cost or labour, which any one may use at home in stead of the natural for the expelling of diseases, and recovering of health. And although I am resolved to set forth a book that shall treat largely of the nature, and original of Baths, and of their use; yet I am willing now also to say something in brief concerning it, and that from the foundation, seeing that there are so many different opinions of learned men, and those for the most part uncertain.