32 



CALORIMETERS FOR STUDYING RESPIRATORY EXCHANGE, ETC. 



Of special interest are the electrical connections on the observer's table 

 itself. A diagrammatic representation of the observer's table with its con- 

 nections is shown in fig. 17. The heavy black outline gives in a general 

 way the outline of the table proper and thus shows a diagrammatic distribu- 

 tion of the parts. The first of the electrical measurements necessary dur- 



RESISTANCE THERMOMETTE.RS 

 WALL AIR REQTAL 



FIG. 17. Diagram of wiring of observer's table. Wi, W 2 , Wheatstone bridges for resistance thermom- 

 eters; Kj, Kj>, double contact keys for controlling Wheatstone circuits; Si, 82, Ss, double-pole double- 

 throw switches for changing from chair to bed calorimeter; S 4 , double-pole double-throw switch for 

 changing from wall to air thermometers; G, galvanometer; R : , rheostat. 1, 2, 3, 4, 5, wires connect- 

 ing with resistance-coils A B D E F and a b d e f; 87, 6-point switch for connecting thermal- 

 junction circuits of either bed or chair calorimeter with galvanometer; Si , 10-point double-throw 

 switch for changing heating circuits and thermal -junction circuits to either chair or bed calorimeter; 

 RI, rheostat for controlling electric heaters in ingoing water in calorimeters; S 5 , double-pole single- 

 throw switch for connecting 110-v. current with connections on table; 89, double-pole single-throw 

 switch for connecting Rj with bed calorimeter. 



