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

  • Haldane, J. S. (John Scott), 1860-1936.
Date:
1920
Catalogue details

Licence: In copyright

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

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    made it absorbs much less rapidly than after it has stood for some time. A stock of it should therefore be kept for recharging the pipette. The pressure in the burette is adjusted by using the potash pipette as a pressure-gauge,andbringing the potash before every reading of the burette exactly to the mark M. As the potash solution has only about one-tenth of the specific gravity of mercury, and with a tube of 2 mm. bore the level can be adjusted very accurately, it is evident that the pressure can be adjusted with great exactitude. In order to make the readings of the burette entirely independent of changes in temperature, barometric pressure, and percentage of moisture during the analysis, a control - tube N, which stands beside the burette in the water-jacket, is employed. The connecting tubes from N are of the same diameter and about the same length as those from the gas- burette; and a three-way tap at P makes it possible to equalise the pressure in N with that of the atmosphere. By means of the T-tube O the potash solution is brought into connection with N. At the beginning of the analysis the potash is adjusted to the mark R bv raising or lowering the potash reservoir S, P being open to the air. P is now turned so that the control tube is connected with the potash tube only, and is not again opened till the analysis is complete. Each time a reading of the burette is made the potash is brought to the mark R by raising or lowering S. The potash in the absorp¬ tion pipette is then brought to the corresponding mark M by adjusting the levelling-tube. The readings of the