118 GEOLOGICAL SUEVEY OF THE TERRITOKIES. 



still be made available for this purpose to a small extent by mixing 

 thQm with charcoal. In A.nstria somewhat similar coals have been used 

 to the extent of one-eighth or one-fourth of the amount of charcoal 

 used.* 



The usual process employed to make coals of low calorific power 

 useful, by driving off the moisture, and concentrating, as it were, the 

 combustible material, is the process of colmig] but this, as we have 

 already seen, fails with these coals. I believe that no coal so far found 

 in my district has been successfully coked. They either crumble to 

 powder in the process, or make such a friable product that it pulverizes 

 in handling or in the furnace. Further south Trinidad coal makes a 

 fair coke, and Canon City coal a poorer one. 



A process has been patented for coking the lignites, but I am in- 

 formed it makes a crumbling, inferior article, unlit for smelting iron, 

 though applicable for light forging. 



To obviate the great loss arising from the easy crumbling of these 

 coals — and the process would improve their behavior in the furnace as 

 well — Professor Lesquereux has suggested the mixing of the coal slack 

 accumulating at the mines with some agglutinizing material and com- 

 pressing the mixture into coherent, blocks ; and for the Western Wy- 

 oming and Utah coals he suggests the use of the bitumen stored in the 

 black shales of the Green Eiver group of rocks near by. Were this to 

 give sufiQcient coherence to the mass, it is certainly an admirable sugges- 

 tion. Many of the substances used for such purposes, as clay, &c., being 

 non-combustible, only subtract from that calorific power in which the lig- 

 nites are originally somewhat defective, while the bitumen would natu- 

 rally assist in their combustion. The enormous accumulations of slack 

 about Eastern and European coal-mines have already led to many ex- 

 periments to render them commercially available. When some of these 

 processes are perfected, their application to western coal-slack may 

 some day form an important industry. 



But any process which can employ directly or which requires a fuel 

 of friable character is the one best adapted to these coals. Heat-pro- 

 ducing appliances have naturally been designed for the use of coherent 

 fuels, and hence these crumbling lignites have failed when used in their 

 stead. Processes, however, have comparatively recently been intro- 

 duced which attain the very highest metallurgical results, and which 

 are yet assisted by the friability rather than by the compactness of the 

 fuel ; and, so far as this character is a factor in the operation, these 

 coals would be admirably fitted for such processes. 



Such processes maybe considered as divided into two classes; namely, 

 those using gaseous fuel, and those using pulverized fuel. The type of 

 the former is the now well-known Siemen's process, with the regenera- 

 tive furnace. Here the coal, or any carbonaceous matter, is first burned 

 in a small, close furnace, called the " Producer," in which the object is 

 to produce, not a high temperature, but a combustible gas. For this 

 purpose the fineness of the coal rather aids the process, for the carbonic 

 acid, formed by the first contact of the air with the lower layer of burn- 

 ing coal on the grate, is then all the more certain, in passing up through 

 the fine mass of incandescent fuel above, to become carbonic oxide, the 

 gas employed in the final operation in themaiu furnace. This process 

 has so far probably been more generally successfully used for the pro- 

 duction of the very highest metallurgical temperatures than almost any 

 other ; and as not ooly lignites, but peat, wood, and even sawdust have 

 been successfully used, and all l3ut the latter for the greatest heats, there 



* Timner's Leob., Jabrb., YI, 186. 



