HXPERIMENTS ON METABOLISM OF ENERGY. r2I 
The figures for the heat given from the urine and feces, as 
shown in the third column in Table 28, are calculated from the 
weights of these excreta, their fall in temperature and their 
specific heats. The weights are found by the balance. The 
fallin temperature is the difference between the temperature of 
the body and that of the interior of the chamber. ‘This differ- 
ence averages about seventeen degrees. The specific heats are 
‘ arbitrarily assumed, that of feces being taken as 0.9 and of 
urine. 10; 
The figures in the fourth column represent the latent heat of 
vaporization of the water given off by the lungs and skin. For 
the rest experiments this water is in general that carried out 
of the chamber in the air current in excess of that brought 
into the chamber by the same current. Ina few rest experi- 
ments, however, and in all the work experiments more or less 
water is condensed on the absorbers and is not carried out by 
the air current. The figures in the third column include the 
heat given off in the condensation of this water vapor upon 
the absorbers along with the latent heat of vaporization of the 
water in the air current. The reason why little or no water was 
condensed on the surfaces of the absorbers in the rest experi- 
ments is that the temperature of the incoming water current 
was asa rule above the dew-point of the air inside the chamber. 
The fifth column shows the heat equivalent of the external 
muscular work done in the work experiments. It is measured 
by the bicycle dynamo apparatus by which the mechanical work 
is transformed into electrical energy and into heat. 
According to the figures of Table 28, in the thirty-seven 
days of the eleven rest experiments the average amounts of 
heat given off per day from the skin (together with that in 
the expired air) was 1,666, in urine and feces 32, and in 
the water vaporized from the lungs and skin 533 calories, 
making the whole daily elimination 2,231 calories. With E. 
O. the range in total heat eliminated was from 2,062 to 2,452 
and the average 2,259 calories. With A. W. 5S. the range was 
from 2,226 to 2,348 and the average 2,279 calories. With J. F. 
S. the range was from 2,065 to 2,297, and the average 2,136 
calories. ‘Taking into account the experiments with all the 
subjects the average amounts of heat given off in different 
ways may be expressed in percentages as follows: 
