THE CALORIMETER. 



13 



it was found to be very difficult to determine exactly the average tempera- 

 ture of so large a mass of air. The difficulties attending this measurement 

 and experiments upon this point are discussed in detail elsewhere.* Con- 

 sequently, as a result of this experience, in planning the calorimeters for 

 the Nutrition Laboratory it was decided to design them for special types 

 of experiments. The first calorimeter to be constructed was one which 



1 Meter 



Fig. 9. — Vertical cross-section erf chair calorimeter from front to back, 

 showing structural steel supporting the calorimeter and the large 

 balance above for weighing the subject inside the calorimeter. 

 The chair, method of suspension, and apparatus for raising and 

 lowering are shown. Part of the heat-absorbers is shown, and 

 their general direction. The ingoing and outgoing air-pipes and 

 direction of ventilation are also indicated. The positions of the 

 food-aperture and wire mat and asbestos support are seen. Sur- 

 rounding the calorimeter are the asbestos outside and hair-felt 

 lining. 



* W. 0. Atwater and F. G. Benedict: A respiration calorimeter with appliances 

 for the direct determination of oxygen. Carnegie Institution of Washington 

 Publication No. 42, p. 91. (1905.) 



Francis G. Benedict: The influence of inanition on metabolism. Carnegie In- 

 stitution of Washington Publication No. 77, p. 451. (1907.) 



