302 Cox. 
hydrogen peroxide which reacts upon the coal to produce carbon 
dioxide. 
There is a marked increase in the weight of Philippine coal 
when exposed to the air, although no definite quantitative deter- 
minations have been attempted on account of the fluctuation of 
the moisture content. Absorbed gases could reduce the calorific 
value of coal by simply adding weight to it; that is, they would 
be merely a diluent. However, if oxygen on being absorbed 
enters into the composition of the coal or unites with the carbon 
or hydrogen of the coal, there is actual deterioration. When 
pure coal becomes oxidized, the total weight and the total heat- 
- ing value are decreased without changing the calorific value of 
what remains. 
The avidity with which coals absorb oxygen is shown by the 
following experiments. Samples of 100 grams each were sealed 
in glass bulbs in an atmosphere of air or oxygen as indicated. 
After a period of twelve months the pressures were measured 
and the gases analyzed as follows: 
TABLE VI.—Analyses of residual gases, when coal is stored with relatively 
small amounts of oxygen. 
e Volume percentages of the 
Dimin- gases after storage. 
Coal} Stored ished 
as a ae Carbon | Remain- 
"| dioxide. | OXYe- |“ der. 
| 
1 air 123 5 0.4 | 94.6 
oxygen 504 75 0.0 b25.0 
a3 air 106 7 ! 0.0 93.0 
3 oxygen 600 69 | 0.0 b41.0 
4 air 70 13 0.0 87.0 
5 oxygen 167 92 0.0 b8.0 
cx air 120 8 0.0 92.0 
| 
8 Vein No. 3. 
b This is accounted for by the inert gas in the commercial oxygen. 
¢ From the East Batan Coal Company mine. 
The above numbers show that the absorption of oxygen by 
coal is complete when an insufficient supply of the former is 
present. 
An apparatus to measure the rate of absorption of oxygen by 
coal, which consists of a barometer for measuring the pres- 
sure within a hermetically sealed space, was devised and con- 
structed as shown in fig. 1. 
