C ! 



CXASS III. 



resin, as they scarcely differ in any thing but in their state 

 of aggregation, which, however, from the perfectly fluid 

 to the solid varieties, forms an uninterrupted series. The 

 mineral oil is first inspissated, and then it is changed 

 into mineral pitch by exposure to the air. Mineral pitch 

 has been divided into elastic, earthy, and slaggy. The first 

 is distinguished by its elasticity, which, however, it loses 

 on exposure to the air, the fracture of the second is earthy^ 

 that of the third more or less perfectly conchoidal, and 

 corresponding to the degrees of lustre it possesses. All 

 these varieties are joined by transitions. 



2. The fluid variety of the present species, called Naph- 

 tha, consists, according to THOMSON and SAUSSURE, of 



Carbon 82-20 87'60. 



Hydrogen 14-80 12-78. 



Mineral oil is. easily inflammable, and burns with a white 

 flame and much smoke. Also the mineral pitch is very 

 inflammable, and burns with a bituminous smell ; some 

 varieties melt in a higher temperature. 



3. The fluid varieties of the present species ooze out of 

 several rocks, as sandstone, slaty clay, &c., or they are 

 found on the surface of springs and other waters. The 

 elastic varieties occur only in the repositories of hexahedral 

 Lead-glance in limestone rocks ; the earthy ones in beds 

 associated with limestone, and probably included in some 

 of the coal formations. The slaggy varieties are often in- 

 cluded in nodules in limestone, in agate balls, in veins, 

 with hexahedral Lead-glance, octahedral Fluor-haloide, 

 &c. ; also in beds. It is met with on the shores and in the 

 waters of the Dead Sea. 



4. Fluid varieties have been found in various districts of 

 Italy, in Sicily, in Zante, in the Caspian Sea, in Persia, 

 and other countries in Asia ; also, though in smaller quanti- 

 ties, in Westphalia and Alsace. Elastic mineral pitch, 

 sometimes called Mineral Caoutchouk, has been hitherto * 

 found only at Castleton in Derbyshire. Earthy mineral 

 pitch is found near Neufchatel in Switzerland, at Grund 

 in the Hartz, in Dalrnatia, &c. ; the slaggy varieties occur 



