Food and its adulterations : comprising the reports of the Analytical sanitary commission of "The Lancet" for the years 1851 to 1854 inclusive, revised and extended being records of the results of some thousands of original microscopical and chemical analyses of the solids and fluids consumed by all classes of the public ... / by Arthur Hill Hassall.

  • Hassall, Arthur Hill, 1817-1894.
Date:
1855
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Licence: Public Domain Mark

Credit: Food and its adulterations : comprising the reports of the Analytical sanitary commission of "The Lancet" for the years 1851 to 1854 inclusive, revised and extended being records of the results of some thousands of original microscopical and chemical analyses of the solids and fluids consumed by all classes of the public ... / by Arthur Hill Hassall. Source: Wellcome Collection.

    702/726
    On the Detection of Sulphate of Zinc in Gin. Tlie snpar, having beon dried, and its weight determined, is to be re-dissolved in distilled water. Half of the solution is to be tested with acid nitrate of baryta for sulphuric acid, and the other half treated with sulphuretted hydrogen, by which means the zinc will be thrown down as a white hydratcd sulphuret, from which, if sufficient of the spirit be used, the metal itself may be separated. We give these directions for the detection of this salt, because it is very probable that it is sometimes used to clarify adulterated gin. On the Presence of Sulphates in Gin. The addition of acid nitrate of baryta to gin, which has not been adulterated with water, should not occasion any precipitation of sulphates, because the water contained in the spirit is all distilled. When, therefore, on the addition of the above reagent, a precipitate is thrown down, this is due either to the presence of free or combined sulphuric acid; if the latter, and there be no sulphate of zinc or iron present, the sulphates are derived either from the water used for the dilution of the spirit, or from the alum employed for clarifying and beading it, so that, alumina being absent, the presence of sulphates affords in all cases a certain indication of the adulteration of gin with water. Out of ten samples of gin to which the baryta test was added, four turned slightly opalescent, but scarcely any deposition of sulphate occurred; while in six of the samples there was a decided, and in three a considerable precipitation. These gins were likewise evaporated, the residues dissolved in a little distilled water, and the solution divided into two parts; to one the acid nitrate of baryta was added as before, when sulphate of baryta was thrown down in every case, and in most in great abundance. Through the other half of the solution sulphuretted hydrogen was passed; in not one instance was any white precipitate observed, from which the absence of zinc is to be inferred. These observations are important, because they afford us the means of judging of the adulteration of gin by the addition of water. Heretofore the presence of water has been inferred rather than proved, from the deficiency of alcohol in the spirit supposed to contain the water. On the Presence of Lead in Gin. As we have seen, it is commonly stated that acetate of lead is employed in the clarification of adulterated gin ; in order, therefore, to ascertain whether the metallic base of this salt is to be found in gin, eight ounces of ten different samples were evaporated, the residues dissolved in a little distilled water, and sulphuretted hydrogen passed through them : in one case a decided brownish discoloration ensued; in some of the others slighter discolorations were ob- served ; but in none of the gins was lead discovered in the ashes treated with nitric acid and water, and tested with iodide of potassium. If lead was, there- fore, present in any of the samples, it was so only in traces. The absence of lead may be explained in some cases even where it has really been used. The lead of the acetate would combine with the sulphates of the water, and the insoluble sulphate of lead would be precipitated; it is, therefore, only when the quantity of lead added is in excess of the sulphates that it would be found in gin ; and when sulphates are present in gin, we may safely conclude that it does not contain lead. From the following Table of Analysis it appears,— 1st. That the strength of the various samples ranged from 15,645 grs. to 34, leOgrs. per imperial gallon; the per-centages ranging from 22-35 to 48*80 per cent. It thus appears, that some of the spirits contained only half as much al- cohol as was present in some of the other samples, and therefore that their commercial value was reduced to the enormous extent of more than one half; thus, supposing sample 2. to be worth 12*. per gallon, sample 35. would bo worth less than 6s. per gallon. This variation in the strength of the spirits is doubtless principally attributable to dilution with water.