The qualities which a liquor ought to possess, in which objects of natural history are placed, are, independently of that of preserving from decomposition: 1. to be colourless, that they may not tarnish the contained objects; 2. not to attack by corrosion the proper colours of the object; 3. to be perfectly transparent, that the contained objects may be visible through the vase which encloses them; 4. the power to resist frost, in order that they may not break the jar which holds them. 1. Spirits of wine, of from fourteen to eighteen degrees of the areometer of Baume, appears to be the liquor which best fulfils all these conditions; the other alcohols, such as those from potato, from grain, from sugar, &c., have the same qualities; but a serious inconvenience is the high price of all of them, and this reason alone is an inducement to look for other compound liquors, capable of replacing them with more or less advantage. 2. Nicholas recommends the following composition: Very pure water, 2 ℔. {pints} Alcohol, 1 ℔. {pint} Sulphate of alumine, 6 ℥. The English naturalist, George Graves, in a work published in London, seven years ago, indicates a liquor which has much analogy with the preceding: Alum, 8 ℥. Common water, 1 ℔. {pint} Alcohol, 1/2 ℔. {1/4 pint} The following is the method of preparing this mixture: the alum is pulverised and put into a vessel capable of resisting heat; water being heated to ebullition is poured upon the alum; when cool, it is to be filtered through gray paper, and then mixed with alcohol. The same author recommends another liquor, thus composed, but of which the mixture is made cold. Common water, 1 ℔. {pint} Alcohol, 1 ℔. {pint} Alum, 12 ℥. 4. The Abbe Manesse, after various trials, more or less successful, has published the result of his experiments; he proposes as the best liquor, one composed as follows: Alum, 1 ℔. Nitre, 1 ℔. Sea salt, 1 ℔. Common water, 4 ℔. {pints} Alcohol, 1 ℔. {pint} The water used should be distilled, so as to be freed of any foreign matter; the alum should be the most transparent that could be obtained, and the salt also should be purified before use. The liquor may be made cold, but it is always better to boil it, with the precaution not to add the spirits of wine until it has cooled. All these liquors are inferior to spirits of wine, inasmuch as they are liable to freeze.