1442. Chemical Method of Procuring Absolute Alcohol

1442.    Chemical Method of Procuring Absolute Alcohol. Take 1 gallon of the alcohol of commerce; throw 1 pound freshly made chloride of calcium into the alcohol, and, as soon as it is dissolved, distill off 7 pints and 5 fluid ounces. Or, take of rectified spirit 1 imperial pint; lime, 18 ounces; break the lime into small fragments, mix with the alcohol in a retort properly connected, and expose the mixture to a gentle heat until the lime begins to slake; then withdraw the heat until the slaking is finished. Now raise the heat gently and distill off 17 fluid ounces. Alcohol thus obtained will have a density, when the operation is carefully managed, of 0.796.

1443. To Increase the Strength of Common Alcohol

1443.    To Increase the Strength of Common Alcohol. Take a pint of common spirits, and put it into a bottle which it will only fill about 3/4 full. Add to it 1/2 ounce pearlash or salt of tartar, powdered as much as it can be without occasioning any great loss of its heat. Shake the mixture frequently for about half an hour, before which time a considerable sediment, like phlegm, will be separated from the spirits, and will appear along with the undissolved pearlash or salt at the bottom of the bottle. Then pour the spirit off into another bottle, being careful to bring none of the sediment or salt along with it. For this purpose an instrument called a separating funnel is well adapted. To the quantity just poured off add 1/2 ounce pearlash, powdered and heated as before, and repeat the same treatment. Continue to do this as often as necessary, till little or no sediment forms; when this is the case, 1 ounce of alum, powdered and made hot, but not burned, must be put into the spirits, and suffered to remain some hours, the bottle being frequently shaken during the time; after which the spirit, when poured off, will be found free from all impurities, and equal to the best rectified spirits of wine.

1444. To Test the Purity of Alcohol

1444.    To Test the Purity of Alcohol. The presence of water may be detected by its specific gravity. Fusel oil may be detected by adding a little of a solution of nitrate of silver to the alcohol. Dissolve 10 grains nitrate of silver in 1 ounce of pure distilled water. Then take half a tumblerful of the suspected liquor and drop into it 25 drops of the above solution; and if the liquid should contain any grain oil, it will assume the form of a black powder and float on the surface. The action of this test is not always immediate, for it is sometimes necessary to wait from 1 to 30 hours when testing a sample of alcohol which has been well rectified, before any evidence of the oil or powder can be perceived floating on the liquid, and even then it is necessary to expose the glass to a strong light before the powder can be discovered.

For detecting fusel oil in alcohol, Mr. E. N. Kent finds pure sulphuric acid the best test. Half fill a test tube with the spirit to be tested, then fill up slowly with pure concentrated sulphuric acid. Pure spirit remains colorless; impure spirit becomes colored in proportion to the amount of fusel oil present. 1 per cent, of wood spirit (wood naphtha) in alcohol, will cause it to turn yellow or brown with the addition of caustic potassa. Pure alcohol is neutral to test paper; should be colorless; will evaporate entirely by heat; retains its transparency when combined with water or ether; tastes and smells vinous.