Present name. - Glacial Acetic Acid.

Concentrated Acetic Acid, corresponding to at least 84 per cent. of anhydrous acid, C4H6O3.

Characters and Tests. - It crystallizes when cooled to 34°, and remains crystalline until the temperature rises to above 48°. Specific gravity 1.065 to 1.066, and this is increased by adding 10 per cent. of water. At the mean temperature of the air it is a colourless liquid, with a pungent acetous odour. 60 grains by weight mixed with a fluid ounce of distilled water require for neutralization at least 990 grain measures of the volumetric solution of Soda. If a fluid drachm of it mixed with half an ounce of distilled water and half a drachm of pure Hydrochloric Acid be put into a small flask with a few pieces of Granulated Zinc, and, while the effervescence continues, a slip of bibulous paper wetted with solution of Sub-acetate of Lead be suspended in the upper part of the flask above the liquid for about five minutes, the paper will not become discoloured.

A notice appears in Allen's Encyclopaedia.

Preparation. - Solution in distilled water.