PLATE XXXV 
Fig. i.—Interior of respiration chamber with subject as seen through the window: 
A, Units of the electric-resistance thermometer for determining temperature of the 
air; B, telephone for communication with observer; C, push button to call observer; 
D, electric fan to stir the air; E, portion of heat-absorbing device described on 
page 316; F, unit of electric-resistance thermometer to measure temperature of copper 
wall; G, small electric lamp for convenience of subject. 
Fig. 2.—Apparatus for regulating and measuring the temperature of water for 
absorbing heat: A, Rheostat in series with heating coil in final heater; B, differential 
motor for adjusting sliding contact on rheostat; C, mechanism for governing activity 
of motor B, in accordance with deflections of galvanometer mounted in the apparatus; 
D, contact keys for shunting field windings of motor B; E, shaft turning cams which 
operate contact keys; F, motor driving cam shaft; G, special Wheatstone bridge for 
differential resistance thermometers, containing also devices for varying the range 
of the slide wire and for checking the precision of the apparatus; H, mechanism for 
shifting balancing contact on slide wire, according to deflections of the galvanometer 
mounted in the apparatus. The slider /, carrying the contact on the slide wire 
mounted in bar K, is moved in either direction by a cord pulled by the shaft bearing 
large wheel L, which is turned by small gears on shaft M, driven by a small motor 
behind the mechanism. A pen carried by the slider draws a temperature difference 
curve showing the movement of the contact on the slide wire. 
