EARTHY MINERALS. 33j 



exhales an agreeable bituminous smell, and burns with a bright 

 white flame on the approach of a lighted taper. Its specific 

 gravity is 0.7. Naptha exists in considerable springs in some 

 parts of Italy, on the shores of the Caspian Sea, in the Caucasus, 

 and other places. It may also be obtained by distilling petroleum, 

 or the tar which is disengaged during the destructive distillation of 

 pit coal, and which is commonly called coal-tar. Naptha bears a con- 

 siderable analogy to the oil of turpentine in its medicinal properties; 

 hence it has been used internally as a sudorific and anti-spasmodic 

 in asthma and chronic catarrh, and externally, as a stimulating 

 application in chronic rheumatism and afflictions of the joints. 

 The dose is from ten to thirty drops. 



2. Petroleum. — Bitume liquide noiratre, Hauy. — Erdol, 

 Werner. — This bituminous substance, known also under the names 

 of Barbadoes and Mineral tar, has long obtained a place in our 

 pharmacopoeias. It is of the consistance of common tar, has a 

 strong disagreeable bituminous odour, and is of a dark blackish 

 brown colour. It exudes abundantly from rocks, generally of the 

 coal formation, in Shropshire, in the territory of Modena and 

 Parma, in Sicily, Persia, and other countries. In its medicinal 

 properties it agrees with naptha, but it is less eligible for internal 

 administration. In Germany it has been extolled as an anthel- 

 mintic in cases of taenia. 



Order III.— EARTHY MINERALS. 



This class comprises all minerals that are composed 

 of one or more earths, either pure, or in combination 

 with the alkalies, with sulphur, with oxygen, or with 

 acids. They are insipid, destitute of true metallic lus- 

 tre, insoluble in water, uninflammable, fixed, and in- 

 capable of being volatalized at a high temperature before 

 the blow-pipe, and their specific gravity is always 

 below 5. 



