Helmersen— Coal of Russia. 265 



plied witli this essential source of motive power. Extensive fields 

 do occur, but these are not distributed generally over the dis- 

 tricts of the Indian empire, but are almost entii'ely concentrated in 

 one (a double) band of coal-yielding deposits, which, with large 

 interruptions, extends more than half across India from near Calcutta 

 towards Bombay. Dr. Oldham has illustrated the areas from which 

 supplies of coal may be looked for with" any prospect of success, by 

 a map, on which are marked those parts of the country of which 

 sufficient knowledge is known to enable him to assert, that there is 

 no probability whatever of any deposits of coal being found within 

 their limits, or where, if coal do exist, it must be found at such a 

 depth below the surface that it could not be economized. On the 

 same map he has indicated, so far as the scale will admit, the true 

 limits and outline of those coal-fields which are known. Of a very 

 large portion of these coal areas detailed examinations have been 

 made, and descriptions published by the G-eological Survey of India. 

 Until all the fields have been carefully mapped, any estimates of the 

 coal resources and production of British India must be defective. Up 

 to the present time it may be said that little more than surface work- 

 ings have been carried on in India. The deepest pits scarcely 

 exceed seventy-five yards, while certainly one-half of the Indian coal 

 which has been used up to the present date, has been produced from 

 open workings or quarries. In forming an estimate of the value of 

 the coal before it has been worked to a sufficient extent to admit 

 of its quality being tested by practice, Dr. Oldham has been guided 

 by a series of analyses of specimens obtained from the several coal- 

 fields. The average composition of 74 specimens of the coal gives — 

 Carbon, 52.2 ; volatile matter, 31.9 ; ash, 15.5. Now as the relative 

 duty or effective power of coals may be taken to vary directly as the 

 amount of fixed carbon which they contain. Dr. Oldham concludes 

 that, out of the whole series of Indian coals, the very best of them 

 only reach the average of English coals, and that on the whole they 

 are very inferior to them. 



III. — The Coal of Eussia. 



By Lieut. -General G. de Helmersen. 



[Des gisements de Charbon de Terre en Eussie. 8vo. St, Petersbourg, 1866, pp. 58.] 



IN this small pamphlet the author discusses the properties, geo- 

 graphical distribution, and present applications of the Eussian 

 coal, and points out in what localities it may profitably be worked. 

 Although our knowledge of the geological constitution of Eussia is 

 far from complete, yet sufficient is known to determine the extent of 

 the workable coal deposits. They have been met with of Tertiary, 

 Jurassic, and Carboniferous age. 



Beds of Tertiary coal occur on the right bank of the Dneiper, near 

 Kier, where they have been worked with profit. Tertiai-y Lignite 

 beds are found in the neighbourhood of Orenbourg ; they are, liow- 

 ever, poor in quality. 



The Jurassic coal is met witli near Koutaiss, in the Trans-Caucasian 



