of German silver can be carried through
the end of the spool and thus allow the insulation to be made much more
satisfactorily. In these calorimeters free use of these thermal
junctions has been made. In the chair calorimeter there are on the top
16 elements consisting of four junctions each, on the rear 18, on the
front 8, and on the bottom 13. The distribution of the elements is made
with due reference to the direction in which the heat is most directly
radiated and conducted from the surface of the body.

While the original iron-German-silver junctions have been retained in
two of these calorimeters for the practical reason that a large number
of these elements had been constructed beforehand, we believe it will be
more advantageous to use the copper-constantin couple, which has a
thermo-electric force of 40 microvolts per degree as against the 25 of
the iron-German-silver couple. It is planned to install the
copper-constantin junctions in the calorimeters now building.

INTERIOR OF THE CALORIMETER.

Since the experiments to be made with this chamber will rarely exceed 6
to 8 hours, there is no provision made for installing a cot bed or other
conveniences which would be necessary for experiments of long duration.
Aside from the arm-chair with the foot-rest suspended from the balance,
there is practically no furniture inside of the chamber, and a shelf or
two, usually attached to the chair, to support bottles for urine and
drinking-water bottles, completes the furniture equipment. The
construction of the calorimeter is such as to minimize the volume of air
surrounding the subject and yet secure sufficient freedom of movement to
have him comfortable. A general impression of the arrangement of the
pipes, chair, telephone, etc., inside the chamber can be obtained from
figs. 7 and 9. The heat-absorber system is attached to rings soldered to
the ceiling at different points. The incoming air-pipe is carried to the
top of the central dome, while the air is drawn from the calorimeter at
a point at the lower front near the position of the feet of the subject.
From this point it is carried through a pipe along the floor and up the
rear wall of the calorimeter to the exit.

With the perfect heat insulation obtaining, the heat production of the
man would soon raise the temperature to an uncomfortable degree were
there no provisions for withdrawing it. It is therefore necessary to
cool the chamber and, as has been pointed ou