OALOKIFIC VALUE OP PHILIPPINE COALS. 177 



tion. In like manner Lebaigne '^ proposed to grind together 0.2 gram of finely 

 powered coal with 2 gi'ams of pure potassium nitrate. In order to lessen the 

 action of the nitrate on the coal, 5 grams of sodium sulphate are mixed in 

 and the whole slowly melted in a silver crucible. When the mass becomes white, 

 then the heat is gradually increased until it is thoroughly fused. The mass is 

 dissolved in water and titrated with sulphuric acid. In order accurately to 

 determine the heating power of a coal by Berthier's method it would be necessary 

 to determine the relation between the carbon and hydrogen, that is, their per- 

 centages by an elementary analysis. It is not surprising that the method has 

 fallen into disuse. However, the process might be of use locally. The coal of 

 a vein or sometimes of an entire region is very similar and a constant empirical 

 factor might be determined which would give good results. 



Goutal's formula as originally proposed applies only to coals capable of 

 being analyzed by the ofBcial method and was not extended to coals 

 where the percentage of fixed carbon in the pure coal is as low as 50 

 per cent. Some time ago I attempted to extend the formula of Goutal 

 to Philippine coal.^* It was thought at that time that the coals of this 

 Archipelago were of the same class as many of the bituminous coals of 

 America. However, sufficient data were not then at hand to demon- 

 strate this fact; more recent work has sho^^oi them to be of slightly 

 lower grade, the volatile combustible matter to be of slightly lower 

 calorific value and large discrepancies occur in their analyses when made 

 by the official method."^ It is a well-known fact that the quantity and 

 character of the volatile products of a coal are influenced by the con- 

 ditions of distillation; by the official method of analysis the rise of 

 temperature in the coal is very rapid and more of the coal is volatilized 

 than by the smoking-ofE method and for this reason if for no other the 

 volatile combustible matter of Philippine coals would appear different 

 from others of the same grade. The calorific value of the fixed carbon 

 of Philippine coal is also slightly lower than that of coking coals. That 

 of pure coke, free from ash, is often greater than that of pure carbon 

 because of the hydrogen from the pitch (hydrocarbon) which charac- 

 terizes a eokuig coal, a part of which is always left as the cementing 

 material in the coke. As a rule, the heating value does not differ 

 materially from that of pure anthracite coal. Goutal gives the average 

 for pure anthracite coal as 8250 calories.^" The heating power of a 

 sample of coke is given as follows : 



"'Bepert. d. Pharmac. (1880) No. 6; Jahresbr. d. chcm. Technol. (1882), 27, 

 990. 



=*Cox, A. J. This Journal, (1906), 1, 877. 



'''Idem, Sec. A. (1907), 2, 41; Sec. A. (1908), 3, 301. 



'' Gompt. rend. Acad. sci. (1902), 135, 479. A similar number is given 

 by The Coal and Metal Miners' Pocket Book, Scranton, Pa. (1902), 168. 



