280 PHILOSOPHICAL TBANSACTIONS. [aNNO 1717. 



find indeed, that their walls seem to bid fair for eternity ; whereas ours, from 

 parsimony and ill management, are scarcely able to endure one age. 



Of the Nature and Virtues of the Pyrmont Waters ; with some Observations 07i 

 their Chalybeate Quality. By Dr. Fred. Slarc, R. S. Soc. N° 351, p. 564. 



Having procured about a dozen quarts of Pyrmont waters, I made some 

 trials of them. I found by the taste that they contained a rich chalybeate 

 virtue,* and also made a lively impression on the palate, more grateful and 

 spirituous, than the best spa-waters I ever tasted. The spa-waters are con- 

 sidered as excellent, if they sparkle a little in the glass : but these in summer 

 time, when poured into the glass, nay sometimes even in the bottle, as soon as 

 the cork was opened, and the air admitted, would make an ebullition, some- 

 what like bottled cyder, though this was soon over ; but they still retained their 

 smart taste, and high chalybeate relish, to the last drop, though we were some 

 hours in drinking them off. In the winter time, these waters neither sparkle 

 nor ferment, at least mine did not ; but they were not carefully preserved, 

 being exposed in cold cellars, where our beer or wine stood in the winter : and 

 yet they lost not their chalybeate taste and their pleasant brisk gout. These 

 waters have been reckoned in the number of the German saur brunnen or 

 acidulaB : and some of my friends, to whom I gave a glass of the water, have 

 ascribed a sharp taste to it, and were apt to think it was sour : but on further 

 consideration acknowledged, that the smart taste misled them to call it acid or 

 truly sour. Thus cyder and soft ale, when bottled, will give such an acute 

 affection to the palate, when it is far from being sour: and even volatile alkalies 

 of sal ammoniac, or of hartshorn, may be made to give the like pungency on 

 the tongue. 



In order to a more nice inquiry into the acidity of these Pyrmont waters, we 

 dropped in considerable quantities both of spirit of hartshorn, and of sal am- 

 moniac, both justly prepared ; but could not discover the least luctation or mo- 

 tion on this conjunction, as is usual with an acid. 



I made a still more nice trial of these waters, by mixing milk with them, 

 sometimes in equal, sometimes in double proportion ; and in various degrees of 

 warmth, from lukewarm to a boiling heat ; but I could not perceive any curd- 

 ling. But rather on the contrary, the water preserved the milk from coagula- 

 tion, for 4 or 5 days, even in September, when hot weather. 



♦ The Pyrmont mineral water, so well analyzed by Bergman, is a carbonated chalybeate water j 

 or a water containing iron held in solution by carbonic acid gas, to which gas the water owes its 

 sparkling property and brisk acidulous taste. 



