ABSTRACT
183. Atmospheric Pressure below Ground Level.—Below the ground, in a mine, the atmospheric pressure is greater than on the surface. The increase of the proportion of oxygen in the air, which follows, does not modify in the least the value of the respiratory exchanges. At the ordinary depths of a mine it cannot be the pressure which causes physiological troubles. All the more so that the increase is very small; the rate of the oxygen varies, therefore, very little, and experiment has shown clearly that the respiration remains normal 1 ) It was found, in this latter case, that the blood was merely momentarily over-saturated; ( 2 ) but this phenomenon must be absolutely uncertain, having escaped a number of observers. ( 3 )
