SUBTERRANEAN GASES. 
263 
but immediately north of the shaft even acetylene lamps were at once extinguished. 
Breathing was very difficult and a feeling of great distress was produced by remain¬ 
ing for only a few minutes in the drift just north of the shaft. It was possible, 
however, to penetrate to a winze 12 feet deep and 100 feet north of the shaft, at 
Midget shaft projected 
Fig. 24.—Longitudinal section showing ventilation in the Conundrum and Midget mines. 
which point a sample of gas was collected by lowering and emptying a bottle filled 
with water. The temperature at this point was +16.7° C. ( + 62° F.). This sam¬ 
ple of gas was analyzed by Mr. L. F. Hawley, of Cornell University, with the fol¬ 
lowing result: 
Analysis of gas from Conundrum mine, March 20, 190If. 
Carbon dioxide. 10. 2 
Oxygen. 5.7 
Nitrogen (by difference). 84.1 
100.0 
On March 21 the mine was again visited. The temperature at the mouth of 
the adit was —2° C. ( + 28° F.), while the barometer stood at 20.2 inches. Work 
was in progress on level 6, but a winze 50 feet deep and 185 feet north of the shaft 
was found to be completely filled with a heavy gas, practically to the level of the 
