"Take of rectified spirit, a gallon; chloride of calcium, a pound. Put the chloride of calcium into the spirit, and when it is dissolved, let seven pints and five fluid ounces be distilled."

Alcohol, Dub. Alcohol.

"Take of rectified spirit of wine, a gallon; pearl ashes, dried, and still hot, three pounds and a half; muriate of lime, dried, a pound. Mix the spirit and the kali; add the pearl ashes, previously reduced to powder, and digest the mixture for seven days in a closed vessel, frequently shaking it; then pour off the spirit; mix with it the muriate of lime; and lastly, distil with a moderate heat, until the residue begin to thicken. The specific gravity of this spirit is to that of distilled water as .810 to 1000."

Syn. Alcohol (F.), Hochst rektifizirter Weingiest (G.), Alcoole (I.).

The following Table, drawn up by Lowitz, with an additional column by Dr. Thomson, shows the Specific Gravity of different Mixtures of pure Alcohol of a Specific Gravity .791, and Distilled Water, at the temperature of 60° and 68° of Fahrenheit.

* Alcohol of the Lond. and the Dub. Pharm. † Ditto (Edin.), rectified spirit (Lond.). ‡ Proof spirit (Lond. Dub.) § Proof spirit (Edin.).

Table, extracted from the Tables of Mr. Gilpin, showing the Real Specific Gravity of different mixtures of Spirit and Water at every 5° of temperature from 50° to 700.1 The standard spirit employed was of the specific gravity 0.825; or contained 89 pure alcohol, and 11 water, in 100 parts.

1 Phil. Trans, for 1794, pp. 320-370. * Alcohol (Edin), rectified spirit (Load.). † Proof spirit (Lond. Dub.)

‡ Proof spirit (Edin.).

Rectified spirit, of the specific gravity of 835°, contains about fifteen per cent, of water; and to free it from this is the intention of the above processes. The affinity of carbonates, alkalies, and chloride of calcium, for water is so much greater than that of spirit, that the water which the rectified spirit contains is attracted by these substances, and prevented from rising with the spirit during the distillation, by which means the alcohol comes over in a highly concentrated state. By means of chloride of calcium, Dr. Black obtained alcohol of the specific gravity of 800°; and Richter procured it so low as 0.796, in the temperature of 60° Fahrenheit1, at which degree of concentration it may be regarded absolute as alcohol, or alcohol nearly free from water. The alcohol of the pharmacopoeias, therefore, is not free from water, but contains about seven per cent. of water. It is, however, sufficiently concentrated for all the purposes of pharmacy.

Qualities. - Alcohol chymically combines with water : the bulk of the resulting mixture is less and its specific gravity greater than the mean of the two liquids before admixture; and much caloric is evolved. It is highly inflammable, burning with a pale yellowish blue flame, the colour varying according to the strength of the alcohol: a blue flame indicates the strongest alcohol. During its combustion, water and carbonic acid are formed, the quantity of the water exceeding that of the alcohol consumed. The alcohol of the pharmacopoeias boils at 176°; and as its boiling point is higher the more water it contains, its strength may be known by the degree at which it boils; allowing for the atmospheric pressure under which it is tried. In vacuo, it boils at 56°. According to Saussure's experiments, it is a compound of carbon 52.17, oxygen 34.79, and hydrogen 13.4 in 100 parts of water2, or it consists of 2 equiv. of carbon = 12.24+ 3 of hydrogen =3 + 1 of oxygen = 8, making the equivalents 23.24 (C2 H3O). It cannot be frozen by any known degree of cold. It dissolves about 60 parts of sulphur, when both the alcohol and the sulphur are in a state of vapour.

It dissolves, also, the carbonic and boracic acids, pure ammonia, soda, andpotassa; volatile oils, resins, and gum-resins; soaps, camphor, sugar, extractive, and the vegetable alkaloids. As a pharmaceutical agent, alcohol, both in its pure and diluted state, is of the utmost importance.

Officinal preparation-Tinctura Acetatis Ferri cum Alcohole, D.