VOL. XXVIII.] PHILOSOPHICAL TRANSACTIONS. 6l 



gentle fire ; the roots are laid upon small transverse pieces of wood over the 

 vessel, and are thus prepared, being covered with a linen cloth, or some other 

 vessel placed over them. They may also be dried in the sun, or by the fire; 

 but then, though they retain their virtue well enough, yet they have not that 

 yellow colour which the Chinese so much admire. When the roots are dried, 

 they must be kept close in some very dry place; otherwise they are in danger 

 of corrupting, or being eaten by worms. 



^n Examen of the Chalybeate, or Spa- Waters. By Dr. Fred. Slare, 

 F.R.S. N** 337, art. 26, p. 247. 



Germany abounds much with these waters, which bear one general name ; 

 they are called sauer-brunns, that is, sour wells or springs of water. The 

 learned Germans call them acidulae, ex. gr. spadenses, swalbaccenses, vel 

 pyromontanae, &c. Henricus ab Heers agrees with Vitruvius, Fallopius, and 

 Helmont, &c. in justifying the acidity of the several sorts of spa and chaly- 

 beate waters; but, not being satisfied with their reasons, assigns others; and 

 after a tedious harangue, concludes, that they owe their virtues to vitriol and 

 sulphur. He observes, that vitriol and sulphur are found in the earth whence 

 these waters spring; but yet does not give one proof or experiment of his 

 having found any real vitriol, or true sulphur, or an acidity in these waters; 

 but fills his book with imaginations, and quotations, exposing other men's 

 ignorance. 



Dr. Jordis, a fellow of the Royal Society, who practised physic at Frankfort, 

 and often at Swalbac in summer-time, gave me an account of some ochres, 

 or ferruginous parts, which he calcined ; but in all his experiments, he did not 

 satisfy me that the water held one drop of an acid by distillation, &c. What 

 gave me the first suspicion, that the chalybeate waters did not contain any 

 rough, or vitriolic, or acid salts in them, proceeded from an accidental use of 

 a strong iron water, in which I dissolved soap, and found it lather and wash 

 my hands well, and then I used a wash-ball and shaved with it; and tried 

 several other waters of this sort, which did the same, and much better than 

 some pump-waters. 



1 . I consulted my palate, and tried whether I could discover any sharpness 

 or acidity in our English steel-waters at Tunbridge, at Black-Boy, in the parish 

 of Franfield in Sussex, Hampstead, Sunning-hill in Berkshire, &c. but I was 

 so far from discovering any such thing, that these waters seemed rather to 

 leave a sweetish flavour behind : thus many alkali salts, of the fixed kind, if 

 nicely examined, have affected my taste. 2. I made experiments with several 

 sorts of such spirits as are apt to ferment with acids; such as spirit of hartshorn, 



