GEOLOGY. 317 







Hydrogen. Carbon. Specific Gravity. 



Asphaltum 9 per ct. 78.10 1.063 



Hillsboro' Coal 1.09 to 1.12 



Cannel 5.66 to 6.00 81.00 1.20 



Bituminous 4.80 to 5.60 81 to 86 1.29 to 1.32 



Anthracite 2.40 to 4.20 89 to 92 1.34 to 1.47 



Graphite none 99 2.27 



The difference in specific gravity and carbon would seem to depend 

 on the diminution of the hydrogen. How this has been separated, 

 whether by the process of time, of pressure, of heat, or, as is most 

 probable, by a process of which we are entirely ignorant, must be a 

 subject for future investigations. 



It must be obvious that the foregoing is but a very faint outline of 

 some of the result of my yet imperfect examination of this subject 

 imperfect mainly because the means of a more perfect one are yet out 

 of reach. The chemical analysis of coal have hitherto been under- 

 taken chiefly with commercial views, and altogether to obtain ultimate 

 principles. But the daily operations of the gas works exhibit pro- 

 ducts showing that yet much has to be done in these analyses to satisfy 

 the increased progress in the science of organic chemistry. My own 

 experience has also led me to the conclusion, that much more remains 

 yet to be accomplished in the study of the internal structure and 

 contents of coal,* and that the vast and varied coal formations of this 

 immense Continent are chiefly to be relied on as the fields for their 

 study. 



* On the application of heat many anthracites separate into laminae as thin as 

 paper. These are alternate layers of hardened resinous hydro-carbon, and of vege- 

 table matter, often retaining in its state of ashes its original forms ; this last is the 

 first hurried out^ leaving the laminae of the former exposed. 



