156 Geology of Uppei' Illinois. 



the discovery of any nearer source of supply. At present, the re- 

 gion referred to, is furnished by the coal mines of Ohio, which 

 are situated one hundred miles from Cleveland, on the Ohio and 

 Erie canal. It would seem however, that coal can be delivered 

 cheaper at Chicago from Rockwell, than at Cleveland, for al- 

 though the distance is the same, yet the dimensions of the Chi- 

 cago canal and its smaller amount of lockage, will give it a de- 

 cided advantage over the Erie canal in the expense of transpor- 

 tation.* 



The quality of coal, so far as can be determined from the lim- 

 ited exploration thus far made of the Illinois beds, is in no way 

 inferior to that of the Ohio coal. It belongs to the variety of bitu- 

 minous coal, known in Great Britain under the name of caking 

 coal, in consequence of the property it has of breaking into a 

 great number of pieces on the application of heat, all of which 

 become cemented together into a solid mass or cake. Its color is 

 grayish black. It has a lamellar or foliated structure, the layers 

 separating from each other with great facility at various inter- 

 vals, from an eighth to three quarters of an inch. Their surfaces 

 often present thin films of what is called mineral charcoal, con- 

 sisting of the remains of various plants, in which the bituminizing 

 process has not taken complete effect. The cross-fracture of 

 these layers is generally resinous and shining, while the slaty 

 surface is dull. It is very easily frangible. Its specific gravity 

 is 1.273.1 It ignites with great facility, and burns with an abun- 

 dant yellow flame. One hundred parts by weight, on being 

 heated, so long as it burnt with a flame lost 47.5 p. c. in weight ,• 

 and the residuum after ignition until all the carbonaceous matter 

 was removed, lost 46.5 in addition ; thus leaving 6 p. c. of ash, 

 which was white, and consisted of silica, oxide of iron, alumina, 

 and lime. 



The ease with which it burns and the abundant flame it emits, 

 must serve to render it a most valuable fuel. For while it will 

 afford a warm and cheerful fuel for the grate, it is peculiarly 

 adapted also to steam boilers, and to all the operations of heat- 



* Coal is raised and delivered to the boats in Ohio, at four cents the bushel. It 

 sells in Cleveland at from fourteen to sixteen cents, and in Chicago, at fifty. 



t One cubic foot of this coal will, therefore, weigh 79^'^-^'^- pounds, which will 

 give for a bed six feet thick in one acre, nine thousand two hundred and thirty 

 one tons. 



