1 82 Mayow 



proper maturity, by the waters which flow from the 

 effervescing mineral. 



Should any one now ask how any mineral can 

 possibly suffice for so long-continued a fermentation, I 

 reply that the earth is imbued in certain places with 

 a mineral seed, which, like vegetable seed, grows and 

 reaches maturity ; and that owing to it the waste of 

 the said mineral is constantly repaired. 



Finally, we remark here that nearly all springs 

 have a certain warmth at their first rise ; and indeed 

 the heat of spring-water just escaping from the earth 

 can be quite sensibly felt in winter when the hand is 

 immersed in it. No doubt the aerial particles which 

 descend with rain-water into the earth effervesce in an 

 obscure motion with the saline-sulphureous particles 

 of which nearly every kind of earth is composed ; and 

 consequently a certain warmth is produced, on which 

 the growth of vegetables depends, as has been else- 

 where shown. And hence it is that spring-waters are 

 for the most part impregnated with acido-saline salts. 

 For if salt of tartar is mixed with spring-water, pre- 

 cipitation usually takes place in it, and, like the 

 aforesaid thermal waters, it becomes whitish — a clear 

 proof of the presence in the water of a salt of an acid 

 nature. And this, too, is the reason that soap does 

 not mix with spring-water ; for the acid salt bf such 

 water contends with the fixed salt of the soap, and so 

 destroys its powers that the sulphureous and oily part 

 of the soap cannot be dissolved in the spring-water by 

 the fixed salt, now subdued, but floats on the surface 

 in accordance with its oily nature. Moreover the acid 

 salt of spring-water seems to be combined with a 

 certain alkaline salt, although the latter be immature ; 

 and therefore it is, that oil of vitriol, when mixed 

 with this water, produces a kind of effervescence. 



