The gas-meter is made by the Dansk Maalerfabrik in Copenhagen, and is of
the type used by Bohr in many of his investigations. It has the
advantage of showing the water-level, and the volume may be read
directly. The dial is graduated so as to be read within 50 cubic
centimeters.
The Elster meter formerly used for this purpose was much smaller than
the meter of the Dansk Maalerfabrik we are now using. The volume of
water was much smaller and consequently the temperature fluctuations
much more rapid. While the residual analyses for which the meter is used
are of value in interpolating the results for the long experiments, and
consequently errors in the meter would be more or less constant,
affecting all results alike, we have nevertheless carefully calibrated
the meter by means of the method of admitting oxygen from a weighed
cylinder.[23] The test showed that the meter measured 1.4 per cent too
much, and consequently this correction must be applied to all
measurements made with it.