An analysis of the medicinal waters of Tunbridge Wells.

Date:
1792
Catalogue details

Licence: Public Domain Mark

Credit: An analysis of the medicinal waters of Tunbridge Wells. Source: Wellcome Collection.

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    with regard to proportion. When this is large, the colour changes immediately, and is always black; but when it is in- coniiderable, it turns out, more or lefs, of a purple; and if the acid be in excefs, as we fuppofe the aerial acid in thefe waters, fome time will be required be¬ fore the colour makes its appearance. To this may be added, the flight pre¬ cipitation produced by lime water, or the alkaline folution (experiment 12th); and more efpecially the light blue co¬ lour, which appeared on the addition of Pruflian lime (experiment 3d): a tefl: fo delicate with regard to iron, that one quarter of a grain may be detected by it in a gallon of water.—The colouring matter combined with lime in this tefl, or, as it is often prepared, with alkali, is what conftitutes the Pruflian blue of the fhops, when united with calx of iron. It appears equally clear that there is alfo contained in thefe waters a quantity D 2