148 English Bituminous Coals. 



The above comparison, shows 'a great similarity in the specific 

 gravity -and the combustible contents of the English coals and those 

 of the valley of the Ohio. Their best cannel and anthracite coals 

 contain a much larger proportion of charcoal. Had the process of 

 coaking, been conducted in the usual way, in close covered vessels, 

 or in the mode pursued in making charcoal from wood, the amount 

 would have been much greater ; a part of the charcoal being con- 

 sumed .with the bitumen, and all the earth and ashes left remaining 

 with the coak. By deflagrating the coals with the nitrate of pot- 

 ash, it is seen, that the proportion of charcoal, or coak, is much 

 greater than here given. Fourteen grains of the purest of this coak, 

 decompose one hundred of nitre, which shows it to be nearly pure 

 charcoal. According to Dr. Ure, one ton of English coal, produ- 

 ces from 1100 to 700 pounds of coak, by the usual process, which 

 is detailed in his chemical dictionary. The bituminous coal of the 

 valley of the Ohio, it is believed, will, whenever the wants of the 

 manufacturer, shall demand its use, more than average this amount. 



Note. — After the description of the coal deposits, in the Monongahela valley, 

 add the following-, which was accidentally omitted in its proper place. 



On the north branch of the Potomac, which rises in the Allegha- 

 ny range, near the line of the Ohio and Potomac canal, especially 

 in the vicinity of the western part of the Savage mountain, a spur of 

 the Alleghany, the deposit of coal is from twelve to twenty feet in 

 thickness — and is said by the Engineer, in one of his reports to the 

 canal commissioners, to average thirteen feet, over an extent of two 

 hundred square miles; and so near to the route of the canal, that it 

 may be passed from the coal mines into boats by means of a slide. 

 The same deposit is continued westward, through the Laurel and 

 Chesnut ridges, but not so thick. It is without doubt a continua- 

 tion of the Monongahela valley deposit, and may be traced north 

 and east, over on to the heads of the Susquehannah river, where it 

 is found in great abundance. In that part of the south branch of the 

 Potomac, which traverses the transition rocks, anthracite coal has 

 been discovered, but to what extent, I have not yet learned. 



