and the weight is recorded. At the beginning of the
experiment the water is deflected from the drain into the meter. At the
end of the period, while the water is running into the small can, the
water-meter is again carefully weighed and the weight recorded. Having
recorded the weight, the water is again deflected into the large meter
and what has accumulated in the small can is carefully poured into the
large meter through a funnel. If the meter is nearly full, so that
during the next period water will accumulate and overflow the meter, it
is emptied immediately after weighing and while the small can is filling
up. About 4 minutes is required to empty the can completely.

After it is emptied, it is again weighed, the water-current deflected
from the small can to the meter, and the water which has accumulated in
the small can carefully poured into the meter. All weights on the
water-meter, both of the empty can and the can at the end of each
period, are checked by two observers.

ABSORBER TABLE.

Shortly after the subject has entered the chamber and in many instances
before the sealing-in process has begun, the ventilating air-current is
started by starting the blower. The air passes through one set of
purifiers during this preliminary period, and as no measurements are
made for this period it is not necessary that the weights of the
absorbers be previously known.

All precautions are taken, however, so far as securing tightness in
coupling and installing them on the absorber system are concerned.
During this period the other set of absorbers is carefully weighed and
made ready to be put in place and tested and about 10 minutes before the
experiment proper begins the residual analyses are begun. The series of
U-tubes, which have previously been carefully weighed, are placed on
small inclined racks and are connected with the meter and also with the
tube leading to the mercury valve. The pet-cock which connects the
return air-pipe with the drying-tower and the gas-meter is then opened
and the mercury reservoir is lowered. The rate of flow of air through
the U-tubes is regulated by a screw pinch-cock on the rubber tube
leading to the first U-tube. This rate is so adjusted by means of the
pinch-cock that about 3 liters of air per minute will flow through the
U-tubes, and as the pointer on the gas-meter approaches 10 liters the
mercury reservoir is raised at just such a point, gained by experience,
as will shut off the