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 measiu-ing 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 

 moimted 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 

 ctirve showing the movement of the contact on the slide wire. 



