﻿THE PROXIMATE ANALYSIS OF PHILIPPINE COALS. 



By Alvin J. Cox. 

 (From the Chemical Laboratory, Bureau of Science.) 



Very few data exist on the relationship between the external ap- 

 pearance and the properties of coal; although we know that a dull coal 

 is apt to be much higher in ash than a lustrous one, and shale, clay frag- 

 ments and similar impurities are readily detected and removed. Still- 

 man 1 says, regarding the mechanically inclosed earthy matter or other 

 ash-forming material: "It is found in practice that coal from the same 

 vein varies in composition with the size of the coal, the percentage of 

 ash increasing as the size of the coal diminishes." He gives analyses 

 of samples collected from the Hanto Screen building of the Lehigh Coal 

 and Navigation Company, Pennsylvania, from which he formulated this 

 general tendency. A corresponding change in specific gravity would 

 probably also have been noted had attention been given to this fact. 

 Perhaps in time some more closely drawn lines of comparison may be 

 forthcoming, but as yet we do not know enough about the connection 

 between the other external characteristics and the composition of a coal 

 to find these factors of much practical value. At present, nothing short 

 of an analysis will satisfy coal investigators. 



An elementary analysis of a coal is of very great importance for 

 scientific purposes, but it shows us little with regard to its value as a 

 fuel. For practical purposes a proximate analysis — that is, the determina- 

 tion of moisture, volatile combustible matter, fixed carbon, ash and 

 sulphur — is of more importance. The figures so obtained give us a very 

 good idea of the real nature of the coal. The moisture and ash are 

 diluents, but more than that, the vaporization of the water entails a 

 considerable loss of heat and the ash hinders complete combustion. The 

 latter fact is shown clearly by the test of Polillo coal 2 at the Insular 

 Cold Storage and Ice Plant, where an analysis of the ash showed it 

 to contain 62.6 per cent of combustible matter. The heat which the 

 ash contains when dropped through the grate constitutes another loss; 

 clinkers formed from the iron and silica of the ash hinder the draft; 



1 Stillman, T. B.: Engineering Chemistry, Easton, Pa. (1900), 25. 



2 The Far Eastern Review, Manila and Shanghai (1906), Jan. ' 



41 



