﻿PROXIMATE ANALYSIS OF COALS. 



0( 



the results obtained by the two methods on coals of the Xegros and Cebu 

 type 13 (Group II) for fixed carbon average about one and a half per 

 cent; as a matter of fact however, the numbers given are undoubtedly 

 larger than the average would be were it possible to eliminate the factor 

 of mechanical loss and obtain a larger and more representative number 

 of coals. 



Table 2 and the tables of analyses of Philippine coals which have 

 already been published 14 show that the content of water varies from 

 5 to 20 per cent. In a number of cases this does not represent water 

 of constitution only, but since the samples are direct from the mine it 

 includes a considerable percentage of loosely held water. This latter 

 is a varying factor and within wide limits is not definite for any partic- 

 ular coal. Attention has already been called to the absurdity of trying 

 to classify coal according to its water content. 15 It might perhaps be 

 said that the more lignitic the character of the coal, the greater the pos- 

 sibility of its including a large percentage of water, but in general the 

 percentage varies with the exposure of the coal, the season of the year. 

 and the state of the weather. It, then, is very important to know what 

 influence, if any. the presence of water has upon the accurate estimation 

 of the volatile combustile matter. To ascertain this the following series 

 of determinations were made by the smoking-off process, with the three 

 samples. To the weighed samples of Batan Island coal and of the 

 Xegros coals definite amounts of water were added and thoroughly mixed 

 in with a fine plantinum wire. The results are as follow-: 



Table 6. 



Grams 



water 



added 



per gram 



Total volatile matter, per cent. 



Batan X0. a 4 Dd C ° al Xe S ros COal N0 " 21 - 



Xegros 

 coal 





1. 



2. 1. 



2. 



Xo. 23. 



0.00 

 0.05 

 0.10 

 0.15 

 0.20 

 0.30 



54.88 

 54.% 



54. 87 50. 22 



50.08 



16 55.15 50.22 

 50.10 



50.2£ 



51.34 



50.27 



51.42 



54.95 

 54.83 



54. 97 50. 34 

 "55.27 50.22 



50.17 



50.27 













13 The striking similarity in both the physical and the chemical behavior of 

 coals from Xegros and Cebu has been constantly in evidence throughout this inves- 

 tigation. Mr. W. D. Smith informs me that all the geology indicates that these 

 two islands are anticlines and that the separating Strait of Tafion occupies the 

 syncline. 

 • "Cox, A. J.: Lor. cit. SS0-SS4. 



15 Idem: hoc. cit.. B8S 



16 A 30 cubic centimeter crucible was used in making these determinations and 

 the results are slightly higher owing to the larger surface on which carbon was 

 deposited. 



