Fossil-Pitch, or Hardened Rock-oil, Petroleum induratum ; a bituminous production (see Bi-tumens), which consists of two varieties.

1. The Asplialtum, or pure fossil-pitch, which is found in the shores of the Dead and Red Seas ; and in various parts of Europe. It is a hard, smooth, brittle substance, destitute of smell, and externally of a black or brown colour, but when exposed to the rays of light, appears of a deep red. - It is chiefly used by watch-dial makers, who mix it with lamp-black, and oil of turpentine. The preparation of this compound is said to be kept secret by certain persons at Stras-burgh. in Alsatia.

2. The Pix montana impura, or Pisasphaltum, which is found in Sweden, Italy, and other parts of Europe. It coheres like slag, or the dregs of iron, and is of the colour of black-lead ; but, if subjected to strong heat, it is soon volatilized ; and, if left in the retort, a liquid substance distils into the receiver, resembling rock oil. - This mineral oil is never used in England as a medicine ; but in France the common people give it in drops for hysteric complaints, and also to their children, with a view to expel worms.