Harrogate and its resources : chemical analysis of its medicinal waters : report addressed to the chairman of the Harrogate Water Committee / by A.W. Hofmann.

  • Hofmann, August Wilhelm von, 1818-1892.
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Harrogate and its resources : chemical analysis of its medicinal waters : report addressed to the chairman of the Harrogate Water Committee / by A.W. Hofmann. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    The quantities of bromine and iodine appear to vary in the several waters, but I am unable to make a positive statement as to this fact, in as much as the different quantities of saline residue left on the evaporation of equal amounts of water compelled me to use very unequal portions for the purpose of testing for bromine and iodine. The quantities of saline residue actually employed were 1500 grains, in the case of the Old Sulphur Well, the Hospital Strong Sulphur Spring, the Montpellier Saline Chalybeate, and the Cheltenham Saline Chalybeate Wells; 750 grains of that of the Montpellier Mild Sulphur Well; and 500 grains in the case of the Montpellier Strong Sulphur W^U, the Hospital Mild Sulphur Spring, and the Starbeck Sulphur Spa ; and lastly 100 grains of the Tewitt^s Well residue. Fluonne.—The fluorine had to be sought for in the insoluble portion of the saline residue of the waters. This residue was tested by Dr. G. Wilson^s excellent process. From 400 to 600 grains of the residue, consisting chiefly of calcareous and magnesian salts, were mixed with a small quantity of pure finely divided quartz, and boiled for about an hour with concentrated sulphuric acid. The terfluoride of silicium disengaged in this manner was passed into water, the re- sulting hydrofluo-silicic acid decomposed by ammonia, and the fluoride of ammonium, after separation of the silica by filtration, evaporated j gently heated with concentrated sulphuric acid in a platinum crucible, this residue disengaged hydrofluoric acid which was recognised by its action upon glass. In the examination of several of the waters, which had deposited rather a large quantity of insoluble matter, the presence of fluorine became at once perceptible on passing into water the gas evolved by boiling, with concentrated sulphuric acid, a mix- ture of the residue and quartz : a floceulent precipitate of silica was thrown down which was considerably augmented on addition of ammonia. In those cases the etching was very rapidly effected, and to a considerable depth; in other cases, however, the separation of silica was scarcely perceptible and the etching very faint. In some cases the etched lines became visible only in the film of moisture produced by breathing upon the glass plates. In none of the waters was found a sufficient amount of fluorine to admit of quantitative estimation. Manganese.—Of all the methods suggested for the detection of small quantities of manganese, none yields more accurate results than the one discovered some years ago by Mr. Walter Crum. It consists in treating the iron precipitate which may contain the manganese