possible,
therefore, to remove all of the outer sections of the calorimeter with
the exception of panels on the east side.

This fundamental change in construction has proven highly advantageous.
It does away with the necessity of rolling the calorimeter out of its
protecting insulating house and minimizes the delay and expense
incidental to repairs or modifications. As the calorimeter is now
constructed, it is possible to get at all parts of it from the outside,
with the exception of one small fixed panel through which the above
connections are passed. This panel, however, is made as narrow as
possible, so that practically all changes can be made by taking out the
adjacent panels.

THE CALORIMETER CHAMBER.

[Illustration: FIG. 7.--Horizontal cross-section of chair calorimeter,
showing cross-section of copper wall at A, zinc wall at B, hair-felt at
E, and asbestos outer wall at F; also cross-section of all upright
channels in the steel construction. At the right is the location of the
ingoing and outgoing water and the thermometers. At C is shown the food
aperture, and D is a gasket separating the two parts. The ingoing and
outcoming air-pipes are shown at the right inside the copper wall. The
telephone is shown at the left, and in the center of the drawing is the
chair with its foot-rest, G. In dotted line is shown the opening where
the man enters.]

[Illustration: FIG. 8.--Vertical cross-section of chair calorimeter,
showing part of rear of calorimeter and structural-steel frame. N,
cross-section of bottom horizontal channel supporting asbestos floor J;
H, H, upright channels (at the right is a side upright channel and to
the left of this is an upright rear channel); M horizontal 8-inch
channel supporting calorimeter; Zn, zinc wall; Cu, copper wall; J,
insulating asbestos.]

The respiration chamber used in Middletown, Connecticut, was designed to
permit of the greatest latitude in the nature of the experiments to be
made with it. As a result, it was found at the end of a number of years
of experimenting that this particular size of chamber was somewhat too
small for the most satisfactory experiments during muscular work and, on
the other hand, somewhat too large for the best results during so-called
rest experiments. In the earlier experiments, where no attempt was made
to determine the consumption of oxygen, these disadvantages were not so
apparent, as carbon dioxide could be determined with very great
accu