Experiments- on the different kinds of Coal. 281 



interest by chemists, mineralogists, geologists, and, particular- 

 ly, by all those who are concerned with coal mines. We shall 

 arrange our view of this work under the following heads : 



1. Preliminary Researches and General Considerations regard- 

 ing Coal, and other combustibles. 



% Chemical Examination of Mineral Coal in general. 



3. Application of the foregoing principles to the Coal-mines of 

 England, France and Germany. 



4. Observations on the Theory of the Formation of Coal. 



1. Preliminary Researches and General Considerations regard- 

 ing Coal and other Combustibles. 



Some naturahsts have asserted, that coal constitutes a true 

 rock formation, or original deposite, and therefore not deriving 

 its origin from vegetables or any other organic matter. A more 

 accurate knowledge of the nature of organic combinations, an 

 advantage which we owe to the progress of chemical sciences, 

 does not permit us any longer to consider coal as a combination 

 of carbon with bitumen. 



The transition of vegetable wood to the mineral which is called 

 Bituminous Wood, or more properly Fossil Wood^ is so manifest, 

 that, in many cases, one might think he could determine with 

 certainty the species of wood which gave rise to the existence of 

 the mineral ; but the more complete the alteration of the vege- 

 table fibres has become, the less striking do the passages of the 

 one substance into the other appear, and the more difficult to 

 recognise. The fossil wood of Iceland, known under the name 

 of Surturbrand, has scarcely any resemblance to wood, at least 

 in cabinet specimens. This substance appears to be a fibrous 

 brown coal or lignite * ; and frequently brown coal is distin- 

 guishable from true or black coal only, because it is surrounded 

 by brown coal less completely altered. By the denomination 

 pitch- coal or jet, is sometimes designated a true coal, sometimes 

 brown coal ; and the columnar coal (stangenkohle) of Mount 

 Meissner, in Hesse, is introduced .into all the systems of mine- 

 ralogy as a true or black coal, although it is nothing else than a 

 brown coal altered by the action of basalt. Brown coal has no- 



Vide Jameson's System of Mineralogy, and Manuel of Mineralogy. 



