Albumen also combines with lime and baryta; and chloride of barium has been recommended in positive printing upon albumenized paper, probably from this cause.
Chemical composition of albumen.—Albumen belongs to the nitrogenous class of organic substances. It also contains small quantities of sulphur and phosphorus.
Alcohol.
Symbol, C{4}H{6}O{2}. Atomic weight, 46.
Alcohol is obtained by the careful distillation of any spirituous or fermented liquor. If wine or beer be placed in a retort, and heat applied, the alcohol, being more volatile than water, rises first, and is condensed in an appropriate receiver; a portion of the vapor of water, however, passes over with the alcohol, and dilutes it to a certain extent, forming what is termed "spirits of wine." Much of this water may be removed by redistillation from carbonate of potash; but in order to render the alcohol thoroughly anhydrous, it is necessary to employ quick lime which possesses a still greater attraction for water. An equal weight of this powdered lime is mixed with strong alcohol of ·823, and the two are distilled together.
Properties of Alcohol.—Pure anhydrous alcohol is a limpid liquid, of an agreeable odor and pungent taste; sp. gr. at 60°, ·794. It absorbs vapor of water, and becomes diluted by exposure to damp air; boils at 173° Fahr. It has never been frozen.
Alcohol distilled from carbonate of potash has a specific gravity of ·815 to ·823, and contains 90 to 93 per cent, of real spirit.
The specific gravity of ordinary rectified spirits of wine is usually about ·840, and it contains 80 to 83 per cent, of absolute alcohol.