III. — AXALYSES OF NoVA ScOTIA CoALS AND OTHER MINERALS. 



— By E. Gilpin, Jr., A.M., F.G.S., Inspector of Mines, Etc. 



(Bead March 9th, 1S91.) 



The following analyses, for the most part hitherto unpublished, 

 may be interesting for comparison. They have been made by 

 the writer, and may be considered as representing fair averages. 



The value of proximate analyses for commercial purposes has 

 certain limits. By its means, in a properly averaged sample 

 representing a bed of coal, the amount of moisture, of ash, and 

 of sulphur, can be determined. The estimations of the amounts 

 of volatile matter, and of fixed carbon, vary with the time of 

 heating, amount of heat, bulk of sample, etc., so that they can be 

 regarded only as approximate. For the same reasons, the gas 

 values of coals are not satisfactorily determined in the laboratory 

 by this method of analysis. The quality of the coke as left in 

 the crucible after determination of volatile combustible matter, 

 is not always found to correspond with that obtained in practice. 



The time and cost of ultimate analyses of coal have prevented 

 their adoption for general commercial purposes, and their value 

 may be based principally upon the view, that as they give the 

 total percentage of carbon present in the coals, they are in accord 

 with the idea that the ultimate evaporative power of a coal is in 

 direct proportion to the amount of carbon it contains. The 

 determinations of sulphur and ash by proximate analysis are 

 equally valuable for ordinary purposes. 



It is remarkable that more attention is not paid by purchasers 

 to the composition and comparative values of the fuels offered 

 to them. The slight differences in prices which are sometimes 

 allowed for coals generally acknowledged to be of lower grade 

 are in many cases disproportionate to the differences really 

 existing. To manufacturers, and other large consumers, the 

 study of this matter would prove a considerable item of profit 

 in balancing cost sheets. 



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