OXIDATION AND DETERIORATION OF COAL. 303 
The portion a 6 d e was made of 
capillary tubing and then at a sealed 
on to an ordinary 100-cubic-centi- 
meter glass pipette f. The tube b 
c is about 800 millimeters long. The 
apparatus was inverted, the coal 
sample inserted through the wide 
tube g which was afterward sealed 
in a gas flame and allowed to cool, 
and finally the apparatus was re- 
turned to its upright position. The 
heavy rubber tubing, dh, is of suffi- 
cient length to allow free movement 
of the mercury vessel 2 over the dis- 
tance 6 c. The vessel 71 was par- 
tially filled with mercury and then 
lowered below c. The apparatus 
was alternately partially evacuated 
and filled with commercial oxygen 
(6.4 cubic centimeters not absorbed 
in alkaline pyrogallol) at e until the 
gas left in f had practically the 
above composition. The vessel 7 
was next raised until the mercury 
in it was level with that in the tube 
¢ e, and the difference in height of 
the mercury in ¢ 6 and ¢ e noted. 
Simultaneous barometric and tem- 
perature readings were always 
made, and from these the exact gas 
pressure in f was calculated. The 
samples used in all of the foregoing 
experiments had been exposed to the 
air for some time previous to the be- 
ginning of the experiment. The 
deterioration, which unquestionably 
begins with the mining of the coal, 
consists in the loss of combustible 
gases, and oxidation already must 
have progressed considerably; 
therefore, the amount of oxidation 
found by the analyses is not nearly 
as great as it would have been if the 
measurements had been begun 
"-7 
B 
i 
s 
S| 
y 
SQ 
Cy Al, ay 
SS re) 
Fig. 1.—Apparatus to measure the rate 
of absorption of oxygen by coal. 
