﻿56 



cox. 



looked for in the results of analyses by the official and the smoking-off 

 methods. 



The official method of analysis is applicable to almost all of the coals 

 of the class of Group I. They give a volume of dense smoke when sub- 

 jected to the influence of heat. The gas produced by destructive distilla- 

 tion from three of the coals of Group I has been analyzed as follows: 



Table 4. 



[The figures give percentages.] 



No. 



Source of the coal. 



Carbon 

 dioxide 

 (C0 2 ). 



Heavy 

 hydro- 

 carbons 

 (C„Ho n ). 



Oxygen 

 (0 2 ). 



Carbon 

 monox- 

 ide 

 (CO). 



Meth- 

 ane 

 (CH 4 ). 



Hydro- 

 gen 

 (Ho). 



Nitro- 

 gen 

 (N 2 ). 



37 



24 



1 



Zamboanga - 



10.1 

 8.4 

 6.24 



6.2 

 8.1 

 6.34 



0.65 



0.7 



0.73 



9.5 



8.95 



5.03 



35.5 

 32.7 

 42. 05 



36.4 

 40.5 

 37.34 



1.65 

 0.65 

 2.17 



Polillo 



Australia . . 



The official method of analysis is only rarely applicable to the coals 

 of the class of Group II. Even the result given for the Batan Island 

 sample which heads the column is too large, owing to mechanical loss 

 of fixed carbon and ash in the estimation of the volatile matter by the 

 official method. Practically all of the coals in Table 2 not included in 

 Group I would be incorporated in Group II except for the large mechan- 

 ical losses. In the extreme case of Negros No. 23 these amount to 10 

 or 12 per cent. The volatile matter which is expelled by the quick ap- 

 plication of heat is in general of a light color and in certain cases colorless. 

 The gas produced by destructive distillation from two coals of Group II 

 has been analyzed as follows : 



Table 5. 

 [The figures give percentages.] 



No. 



Source of the coal. 



Carbon 

 dioxide 

 (C0 2 ). 



Heavy 

 hydro- 

 carbons 

 (C n H 2n ). 



Oxygen 

 (0 2 ). 



Carbon 

 monox- 

 ide 

 (CO). 



Meth- 

 ane 

 (CH 4 ). 



Hydro- 

 gen 

 (H 2 ). 



Nitro- 

 gen 

 (N 2 ). 



4 



21 





26.04 

 17.44 



2.31 

 3.21 



0.43 

 0.05 



14.15 

 7.15 



16.9 

 34.43 



35.4 

 34.48 



4.77 

 3.24 



Negros ___ __ - 





Tables 1+ and 5 show that the heavy hydrocarbon content of the gases 

 produced from the coals of Group I is about three times as large as that 

 from the coals of Group II; Table 3 shows that the difference in the 

 results for fixed carbon obtained by the official and the smoking-off 

 methods in the analyses of the coals is much greater in Group I than in 

 Group II; hence it is evident that this difference varies with the com- 

 plexity of the volatile constituents of the coal — that is, that the varia- 

 tion »s due largely to the difference in the breaking down of the volatile 

 ingredients. The data given in Table 3 indicate that the difference in 



