891 
The gas analyses were made according to standard methods. The 
methane and hydrogen were determined by explosion over mercury and 
the nitrogen by difference. 
The calorific value of the coal was figured according to the formula 
given on page 878. 
The calorific value of the gas was calculated at 30° from the following numbers 
of J. Thomsen: ® For the heat of formation of water from hydrogen, Thomsen ~ 
obtained, as an average of three very closely agreeing numbers, the value H,O+ 
O—H,0+68,388 calories. The heat of combustion of methane has often been 
determined and the number obtained under the most painstaking conditions by 
Thomsen,” and a fair average of the reliable values of other investigators is, 
CH,+-40=CO,+-2H20-+ 211,900 calories. The heat of combustion of ethylene, 
according to the measurements of Thomsen, is C,H,+60=52CO,+2H,0+333,300 
calories. The number obtained by Thomsen for carbon monoxide has not been 
used, but by preference the round value recommended by Ostwald,?* which lies 
between those obtained by J. Thomsen™ and Berthelot,” i. e., CO+O—=COo+ 
68,000 calories. One gram molecule of a gas==22.32 liters under standard 
conditions. 
The following factors have been figured from the foregoing data :*° 
Calories per ¢. ¢. 
Carbon monoxide (CO) 2. 744 
Heavy hydrocarbons (C, H,,,)?* 18. 455 
Methane (CH,) 8. 553 
Hydrogen (H,) 2. 756 
The gas-producing power of five native coals has been determined. 
For the purpose of comparison a very superior, coking, Australian 
steaming coal has also been investigated. 
RESULTS. 
A sample of coal from Batan Island ** gave the following results : 
* Thomsen, J.: Thermochemische Untersuchungen, 11. 
%Tdem: Loe. cit., 44; Pogg. Ann. (1873), 148, 368. 
77Tdem: Loe. cit., 94. 
* Ostwald, W.: Lehrbuch allg. Chem. p. 173. 
Thomsen, J.: Loc. cit., 284. 
* Berthelot: Ann. Chim. Phys. (1878), (5) 13, 11. 
“Tf it is desired to compare in any way these numbers with those of the 
Report on the Operations of the Coal-testing Plant at the Louisiana Purchase 
Exposition, St. Louis, Mo., 1904, U. 8S. G. S., P. P. 48 (1906), 3, Producer-gas, 
ete., it must be remembered that in each of the last three lines on page 1004 
“per ec. ¢.” should read, per percentage-content. 
*T All the heavy hydrocarbons are assumed to be present as ethylene. This 
probably gives too low a result, but the error is on the conservative side. 
**'This was taken from the southeastern end of the island. It is a well-known 
fact that the coals from this region are of a much poorer grade than those from 
the western end. 
