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The famous boiling spring near Montpelicr is likewise 

 no other than common water, through which a vapour 

 of the same kind makes its way; indeed, ail the springs 

 thereabouts bubble more or less, the vapour making 

 its way through the whole surface of the earth. Water 

 taken out of that spring has no such property nor any 

 peculiar taste or virtue. What is a farther proof is, the 

 . cracks of the earth thereabout* all perspire strongly a 

 vapour of this kind ; so that if straws be laid on the sur- 

 face they will be blown up; and if a hole be any where 

 Hug in the ground, and water poured into it, it will 

 boil up in the same manner as the spring. 



The like sort of springs are common in Switzerland, 

 and some other places: these are known to be owing to 

 effluvia from beneath, by tli water of them being cold. 

 But there are others which actually boil, and are hot 

 enough to boil an egg : such are the famous boiling 

 fountains of Solfatara, near Naples. 



From these various springs we find that there is much 

 variety of this kind of exhalations : some being cold 

 a*xl dry, some of a bituminous nature, and not actually 

 cold, as our's in Lancashire ; some hot, as those in the 

 sweating vaults and caverns, and in the mountains of 

 Italy. Others are of a poisonous nature, containing 

 particles of arsenic, or other poisonous minerals. 



6. Many bodies are tasteless ; but some even of 

 these may contract a very strong taste (as do several 

 metals) when they are resolved into a fine powder. 

 Some bodies by several other changes, acquire tastes, 

 which they had not before, or variously increase, lessen 

 or alter their taste. Hence it has been supposed that 

 all tastes proceed from salts, which are often so envelop- 

 ed, that they cannot exert their power. But if the con- 

 taining bodies are dissolved by fire or liquors, then they 

 variously afreet the nerves in' the tongue and palate : 

 and hence arise all the various sensations of taste. But 

 what particular size, shape, or motion of the particles is 

 required to produce any particular taste, ail our skill 

 cannot determine. 



