CCLXXXII.—On dopplerite. Studies in the composition of coal

Frederick Vincent Tideswell, Richard Vernon Wheeler
1922 Journal of the Chemical Society Transactions  
WE believe that considerable insight into the mode of formation and constitution of coal, and in particular of certain portions of bituminous coals, can be obtained from a study of that peculiar material to be found in peat-'bogs, to which the name " dopplerite " has been given. Unfortunately, this material belongs to that class of compounds, the ulmin compounds, the colloidal nature of which is so discouraging to the chemist. For this reason, no doubt, information regarding the composition and
more » ... the composition and properties of dopplerite is scanty and scattered, although descriptive accounts of it are numerous in the literature of coal. It will be necessary for us to review shortly the information that is available. As early as 1839 reference was made to peculiar deposits in the peat-bogs of the Fichtelgebirge by Reinsch ( J . pr. Chem., 1839, 36, 489), who alluded to them as " Pechtorf " in contradistinction to " Rasentorf " (ordinary peat), but no detailed examination of them was made until 1849, when Doppler had his attention directed to one in a peat bed at Aussee, in Tyrol, and thought it of sufficient importance to warrant investigation. It was described as a black, gelatinous substance, occurring in layers about 10 feet in thickness 6 or 8 feet below the surface of the bog. Doppler's examination of the black jelly (Sitxungsber. Akad. Wiss. Wien, 1849, 3, 239) showed it to contain a high proportion of water (it lost 80 per cent. of its weight on drying) and when anhydrous to be a brittle, shining, black substance with a conchoidal fracture. The fresh substance, on exposure to the air, lost its moisture rapidly and became elastic and of the consistency of indiarubber ; it was insoluble in water, sparingly soluble in alcohol and ether, but readily soluble in a solution of potassium hydroxide. A further examination of material from the same source was made by Schrotter (chemical) and Haidinger (microscopical), who confirmed and added to Doppler's observations (ibid" p. 285). Haidinger observed that thin sections showed no trace of crystalline substances when viewed by polarised light, but that under high magnification traces of fibres of organic origin could be discerned. This latter statement, and the fact that the material in bulk was not uniformly glossy and of a dark-brown, almost black, colour, but contained dull streaks of a hghter brown, indicate that the VOL. CXXT. L
doi:10.1039/ct9222102345 fatcat:q2jmbeu4rrglbgk6rgv7ngu2ry