NOV. 22, 1915 
Improved Respiration Calorimeter 
345 
accuracy of the determinations when heat was produced in the chamber 
at a rate of about 120 calories per hour. For all four factors the quan¬ 
tities determined were slightly larger than those computed from the 
composition of the alcohol, the discrepancies amounting to 1.5 per cent 
for oxygen, 0.7 per cent for water, and the same for heat, and 0.2 per 
cent for carbon dioxid. The respiratory quotient—i. e., the ratio of the 
volume of carbon dioxid produced to that of oxygen consumed in the 
combustion of alcohol—is 0.667; in the test the ratio of the values found 
was 0.658. Similarly, the ratio of the number of Calories of heat pro¬ 
duced to the number of grams of carbon dioxid produced is theoretically 
3.705, whereas in the test it was 3.725. 
Table II .—Data obtained in the combustion of alcohol in the respiration calorimeter 
Oxygen. 
Water. 
Carbon dioxid. 
Heat. 
Quotients. 
Date. 
Found. 
Re¬ 
quired. 
Found. 
Re¬ 
quired. 
Found. 
Re¬ 
quired. 
Found. 
Re¬ 
quired. 
Respir¬ 
atory 
(CO 2 : 
O 2 ). 
Ther¬ 
mal 
(Cal.: 
COs). 
Nov. 21, 1913... 
Feb. 18, 1915. .. 
Gm. 
105. I 
139.0 
Gm, 
103. 6 
140. 7 
Gm. 
65-4 
97-3 
Gm. 
64.9 
9»- 5 
Gm. 
95 - 1 
142. 5 
Gm. 
94.9 
143-9 
Cal. 
354-2 
535- 8 
Cal. 
35 1 - 7 
533-3 
0. 658 
.669 
3- 725 
3- 759 
In February, 1915, in a 6-hour period, 85.35 g m * of commercial alcohol 
containing 88.25 per cent of ethyl hydroxid were burned, the rate of pro¬ 
duction of heat being about 90 Calories per hour. In this test the heat 
measured by the calorimeter was nearly 0.5 per cent greater than that 
computed, whereas the quantities of oxygen, water, and carbon dioxid 
measured were 1 to 1.3 per cent lower than those computed. 
Another test made at frequent intervals provides a check on the accu¬ 
racy of the calorimetric function of the apparatus. Electric energy is 
converted into heat within the chamber, and the amount produced in a 
given period, which can be computed very accurately, is compared with 
that measured by the calorimeter during the period. The electric energy 
is converted into heat in a coil of resistance wire suspended in the cham¬ 
ber. The amount of energy that is dissipated is computed from the 
values for the voltage and amperage of the current in the coil, the time 
in seconds, and the factor for converting watt seconds to small calories 
at 20 0 C., as explained on p. 342. 
The resistance of the heating coil depends upon the desired heat pro¬ 
duction, the majority of the tests having been made with a coil having a 
resistance of 440 ohms, which allows 0.5 ampere of current to flow with 
a fall of potential of 220 volts. The resultant heat is approximately 95 
Calories per hour, or about that produced by an average man sitting 
still. That the rate of production of heat may be constant, the voltage 
of the current is controlled by an automatic regulator; but the actual 
fall in potential is measured by a voltmeter connected to the terminals 
