t, the cooling is
accomplished by passing a current of cold water through a heat-absorbing
apparatus permanently installed in the interior of the chamber. The
heat-absorber consists of a continuous copper pipe of 6 millimeters
internal diameter and 10 millimeters external diameter. Along this pipe
there are soldered a large number of copper disks 5 centimeters in
diameter at a distance of 5 millimeters from each other. This increases
enormously the area for the absorption of heat. In order to allow the
absorber system to be removed, added to, or repaired at any time, it is
necessary to insert couplings at several points. This is usually done at
corners where the attachment of disks is not practicable. The total
length of heat-absorbers is 5.6 meters and a rough calculation shows
that the total area of metal for the absorption of heat is 4.7 square
meters. The total volume of water in the absorbers is 254 cubic
centimeters.

It has been found advantageous to place a simple apparatus to mix the
water in the water-cooling circuit at a point just before the water
leaves the chamber. This water-mixer consists of a 15-centimeter length
of standard 1-inch pipe with a cap at each end. Through each of these
caps there is a piece of one-eighth-inch pipe which extends nearly the
whole length of the mixer. The water thus passing into one end returns
inside the 1-inch pipe and leaves from the other. This simple device
insures a thorough mixing.

The air-pipes are of thin brass, 1-inch internal diameter. One of them
conducts the air from the ingoing air-pipe up into the top of the
central dome or hood immediately above the head of the subject. The air
thus enters the chamber through a pipe running longitudinally along the
top of the dome. On the upper side of this pipe a number of holes have
been drilled so as to have the air-current directed upwards rather than
down against the head of the subject. With this arrangement no
difficulties are experienced with uncomfortable drafts and although the
air enters the chamber through this pipe absolutely dry, there is no
uncomfortable sensation of extreme dryness in the air taken in at the
nostrils, nor is the absorption of water from the skin of the face,
head, or neck great enough to produce an uncomfortable feeling of cold.
The other air-pipe, as suggested, receives the air from the chamber at
the lower front and passes around the rear to the point where the
outside air-pipe leaves the c