94 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



Von GiimbeP^^ made an elaborate study of Dopplerit in 1858. 

 He found that the Berchtesgaden dopplerite dififers in some respects 

 from that of Aussee. After drying in air, it gives off 12 per cent, 

 of water at 100° C. ; when heated to red heat in a closed vessel, it 

 yielded 66.33 per cent, of non-coherent coke, retaining the form of 

 the original fragments. The ash is but 1.67 per cent, of the dried 

 material and consists mostly of lime. Treated with absolute alcohol, 

 it yields a considerable quantity of resinous matter, which v. Giimbel 

 thinks consists of two resins. The variability of composition at dif- 

 ferent localities leads him to believe that dopplerite is not a true 

 mineral, but is merely a homogeneous peat and he suggested instead 

 the term Torfpechkohle because 'oi its resemblance to the Tertiary 

 Pechkohle. The mode of occurrence at Berchtesgaden is peculiar, 

 the succession in the pits being (a) Rasen- and Moorerde; (b) 

 Specktorf ; (c) Fasertorf ; (d) Specktorf ; (e) Fasertorf with roots; 

 (/) gray marl; (g) calcareous pebbles. (/) is almost impervious to 

 water. The Torfpechkohle is found chiefly between (d) and (e), 

 but (c) contains much of it in irregular streaks. Two vein-like 

 branches pass upward from the main deposit overlying (e) and con- 

 tinue through the higher benches into (a). He is convinced that the 

 material was soft and that under pressure it flowed into crevices. 

 This feature suggested that plant materials were softened as one 

 step in the conversion into coal. 



Kaufmann^^" received specimens of a lustrous black coal, occur- 

 ring in a peat layer at Obburgen in Unterwalden, Switzerland. It 

 agrees with dopplerite in all essential features. The material was 

 from a Hochmoor, where it was found at 12 to 14 feet below the 

 surface and in masses 6 inches to a foot thick, embedded in the 

 black peat; but it often occurs as veins, streaks or nests. When 

 fresh, it is gelatinous but it becomes hard on drying; it is odorless, 

 has greasy luster and mahogany streak; softer than talc, it cracks 

 under pressure. Examined under the microscope it is homogeneous, 



^35 C. W. V. Gumbel, " Ueber das Vorkommen des Torf-Pechkohle (Dop- 

 plerit) im Dachelmoos bei Berchtesgaden," Neiics Jahrbuch, Jahrg. 1858. pp. 

 278-286. 



^'■^'^ F. J. Kaufmann, " Ueber den Dopplerit von Obburgen und viber das 

 Verhaltniss des Dopplerit des Torf und mineralischen Kohlen," Jahrb. k. k. 

 Geol. Reichsanst., Bd. XV., 1865, PP- 283-290. 



