Methods of air analysis / by J.S. Haldane.

  • John Scott Haldane
Date:
1920
Catalogue details

Licence: In copyright

Credit: Methods of air analysis / by J.S. Haldane. Source: Wellcome Collection.

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    trough used in transferring the air from the bottle into the gas-analysis apparatus. For the same reason large bottles are very unsuitable, apart altogether from the great inconvenience in carrying them about. The sample is collected as follows. One end of a piece of rubber tubing about two or three feet long, and £ or | inch in internal diameter, is introduced into the bottle to the bottom, the other end of the tube being held in the mouth. A deep breath of air is then sucked in through the tube. The bottle is in this way very thoroughly washed out by the incoming air, since the volume of air sucked through will be more than ten times as great as the capacity of the bottle. The tube is removed while the air is still being sucked up, so as to avoid any risk of breath passing backwards into the bottle. The stopper is then inserted, turned round, and secured as already described, and the particulars written on the label. When the gas to be examined is issuing from a pipe or bore-hole a sample may be obtained by arranging a piece of rubber or bent glass tube so as to pass through a plug of clay inserted in the end of the pipe. The free end of the tube is then placed in the bottle, which must be inverted if the issuing gas is lighter than air. The stopper must, of course, be inserted as soon as the tube is withdrawn. When samples are collected over water, or by emptying vessels of water, the carbon dioxide percentage is not reliable, as the water or wet bottle may have absorbed some of the gas, or the water may have given off carbon dioxide to the air. Samples collected in metallic vessels
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