Contractions. - Petr. Pet. Synonym. - Oleum Petrae Album. Petroleum. For. name: German, Steinol.

The name Petroleum is employed so loosely to designate numerous liquid hydrocarbons, that it is important to insure the use of the same substance which Hahnemann employed in his proving. This is made by agitating the liquid portion of Commercial Petroleum with Sulphuric Acid, and then rectifying the portion which this acid does not act upon. Its chemical constitution is very complex.

Characters and Tests. - A light oily fluid, colourless, or of a pale straw colour, and strong characteristic naphthalic smell. "When agitated with a mixture of equal volumes of Sulphuric Acid and water, no change takes place beyond its imparting to the acid any yellow tint it may possess and itself becoming colourless. Dropped on white paper, it evaporates completely, leaving no greasy stain. To secure its freedom from other volatile oils, agitate with twice its bulk of rectified spirit, and filter through bibulous paper previously moistened with rectified spirit, or it may be separated from the spirit by means of a burette. It must be preserved in well-stoppered bottles.

Preparation. - Solution in rectified spirit.

Reference to Horn. Proving. - Chr. Kr., iv.

Proper forms for dispensing. - lx and upwards, Tincture, Pilules, or Globules.