GEOLOGY. 269 



The excellence of the Cumberland coal is attested by many men 

 of science. Mr. David Mushet, of Gloucestershire, a few years ago, 

 pronounced some specimens from near the town of Cumberland 

 " the very best bituminous coal he had ever met with," and he con- 

 sidered it well adapted to iron making. Dr. Ure says that it " re- 

 sembles closely, in external appearance, the outcross coals of the 

 Monkland and Calder district, near Glasgow, so celebrated for mak- 

 ing good iron." "Professors Silliinan, Shepard, and others, have 

 shown," says Mr. Taylor, "that the main or ten feet Frostberg 

 seam, which, having been longer worked, has conferred a character 

 on the Cumberland coal, contains but 13.34 per cent, of bitumen, be- 

 sides 1.66 of water. Such an amount as 82 per cent, of carbon, 

 which these analyses show it to possess, while at the same tune it 

 retains enough of the properties of flaming coal, carries its own best 

 commendation, and places it very high, if not the highest, in the 

 scale of American coals." Opinions might be added from Prof. 

 Daniel, Major Douglas, Dr. Jackson, Prof. Ducatel, Lieut. Lynch, 

 Prof. Renwick, and others. 



Being of an intermediate kind between the anthracite and full 

 bituminous, and having more carbon than the latter, and more bitu- 

 men than the former, the semi-bituminous coal possesses a high de- 

 gree of the good qualities of both, although not so high of either of 

 those of which the others have an excess. It contains these ele- 

 ments in more equal proportions. In anthracite the average of car- 

 bon is from 90 to 95 parts out of 100; in bituminous, 45 to 55 out 

 of 100. For extremely hot fires, like that of charcoal, the anthra- 

 cite is, of course, the best. For a fast open-burning fire of little in- 

 tensity, the English bituminous coals are best. But used for the 

 purposes of the locomotive engine, propelling either ship or car, the 

 anthracite, although possessing ample evaporative powers, is too dif- 

 ficult to kindle for the despatch and punctuality of travel, and it re- 

 quires blowers and a strong draft to keep it burning, the consequence 

 of which is, that a large proportion of heat (estimated at 20 per cent.) 

 is lost, so that less steam is obtained than from coals of intrinsically 

 less evaporative power. At the same time, the incomplete combus- 

 tion of this coal, leading to frequent and inconvenient accumulations, 

 which choke the furnaces, and its tendency to clinker, are almost 

 fatal objections to its use, alike on railways and steamers. 



On the other hand, the common English bituminous coal, which 

 has heretofore been much used in steamships, and is very good, has 

 not a few objectionable qualities. The immense volumes of smoke 

 it emits is a point not be overlooked, in connection with its applica- 

 tion to naval purposes. The bituminous coal has the advantage of 

 kindling quickly, and it burns fast. But its heating power is less 

 than that of the semi-bituminous, of course much less than that of 

 anthracite. A larger bulk of this coal is, therefore, necessary for the 

 same amount of evaporative power. The tendency of this coal to 

 run together or cake as it burns, is also not to be overlooked. And 

 instances have occurred of bituminous coal igniting by spontaneous 

 combustion on board of ships. This has been the case with vessels 



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