1 74 Mayoiv 



Lastly, as regards vitriol, the bath usually called the 

 Cross Bath, and also the one named the Hot Bath, 

 appear to contain no vitriol whatever. For if pounded 

 gall-nuts are infused in the waters of the said baths, 

 the waters will by no means assume a purple or a 

 black colour, and yet this would certainly be the case 

 if these waters were imbued with vitriol. With 

 respect to the so-called King's Bath, it seems to be 

 impregnated with a little vitriol ; for if pounded gall- 

 nuts are put into its water, it will be slightly tinged 

 with a blackish-purple. 



But it should be noted that along with the gushing 

 waters of the said hot springs, there rushes out from 

 the earth a mineral of a metallic nature which can 

 easily be changed into vitriol. For if any acid liquid 

 is poured on the san^ which escapes from the earth 

 along with the water of the hot springs and is found 

 at the bottom of the baths, this sand, when corroded 

 with considerable effervescence by the acid menstruum, 

 will in part be turned into vitriol, just as iron filings 

 are when corroded by an acid liquid. For if that 

 sand of the baths, when impregnated with an acid 

 liquid, be added to an infusion of galls, the liquid will 

 at once acquire a dark purple colour ; while, on the 

 other hand, if the infusion of galls be poured upon 

 the sand when taken fresh from the baths (but not 

 yet corroded by an acid liquid), it will not become 

 purple at all — undoubtedly a clear proof that the 

 metallic sand of the baths assumes the vitriolic nature 

 only when corroded by an acid menstruum. It is to 

 be noticed also that this sand of the hot springs will 

 spontaneously change into vitriol if kept for a con- 

 siderable time and exposed to the air ; for if such 

 sand is put into an infusion of galls, the water will at 

 once take a dark purple colour. Nay, if it be put on 



