Contractions. - Fluor. Ac. Fl.-x.

Present name. - Hydrofluoric Acid. HF. For. name: German, Fluorwasserstoffsaure.

Prepared by distilling pure Fluorspar (Calcium Fluoride) in a state of fine powder with Sulphuric Acid. As the acid dissolves glass, the distillation must be performed in platinum vessels, and the acid can only be preserved in bottles of the same, or in bottles made of gutta-percha. It should be purchased from the operative chemists, guaranteed as having been prepared as above, and re-distilled.

Tests. - Place a drop of the aqueous solution on a slip of glass, let it remain a few minutes, then wash it off, and hold the glass so that the eye may glance over the polished surface, when the spot where the liquid was will be found to have entirely lost its polish, some of the glass having been dissolved.

Preparation. - An aqueous solution of 1 in 10. Water must be used for making the first three dilutions, and all these must be kept in gutta-percha bottles.

Reference to Horn. Proving. - Transactions of Amer. Inst., vol. i.

Proper forms for dispensing. - Below 4, watery Solution only. 4, dilute Tincture. 5 and upwards, Tincture, Pilules, or Globules.