Page:Popular Science Monthly Volume 26.djvu/694

676 of Science" of April, 1877. The editor adds that the inventors of this paper have discovered a method of removing the magenta from wines without injuring their quality, "a fact of some importance, if it be true that several hundred thousand hectolitres of wine sophisticated with magenta are in the hands of the wine-merchants" (a hectolitre is equal to twenty-two gallons).

Another simple test, that was recommended at the time, was to immerse a small wisp of raw silk in the suspected wine, keeping it there at a boiling heat for a few minutes. Aniline colors dye the silk permanently; the natural color of the grape is easily washed out. I find, on referring to the "Chemical News," the "Journal of the Chemical Society," the "Comptes Rendus," and other scientific periodicals of the period of the phylloxera-plague, such a multitude of methods for testing false-coloring materials that I give up in despair my original intention of describing them in this paper. It would demand far more space than the subject deserves. I will, however, just name a few of the more harmless coloring adulterants that are stated to have been used, and for which special tests have been devised by French and German chemists.

Beet-root, peach-wood, elderberries, mulberries, logwood, privet-berries, litmus, ammoniacal cochineal, Fernambucca-wood, phytolacca, burned sugar, extract of rhatany, bilberries; "jerupiga" or "geropiga," a "compound of elder-juice, brown sugar, grape-juice, and crude Portuguese brandy" (for choice tawny port); "tincture of saffron, turmeric, or safflower" (for golden sherry); red poppies, mallow flowers, etc.

Those of my readers who have done anything in practical chemistry are well acquainted with blue and red litmus, and the general fact that such vegetable colors change from blue to red when exposed to an acid, and return to blue when the acid is overcome by an alkali. The coloring-matter of the grape is one of these. Mulder and Maumené have given it the name of œnocyan or wine-blue, as its color, when neutral, is blue; the red color of genuine wines is due to the presence of tartaric and acetic acid acting upon the wine-blue. There are a few purple wines, their color being due to unusual absence of acid. The original vintage, which gave celebrity to port wine, is an example of this.

The bouquet of wine is usually described as due to the presence of ether, œenanthic ether, which is naturally formed during the fermentation of grape-juice, and is itself a variable mixture of other ethers, such as caprilic, caproic, etc. The oil of the seed of the grape contributes to the bouquet. The fancy values of fancy wines are largely due, or, more properly speaking, were largely due, to peculiarities of bouquet. These peculiar wines became costly because their supply was limited, only a certain vineyard, in some cases of very small area, producing the whole crop of the fancy article. The high price once