190 



MAX KLEIBER 



by good insulation alone {i.e., make L in equation 12 small). This was 

 accomplished in Capstick's calorimeter for large animals {22). 



Decrease or prevention of heat flow through walls may also be ac- 

 complished by adiabatic jackets. An adiabatic jacket consists of two 

 concentric metal walls with air or a liquid lietween them. When the 

 two walls are kept at the same temperature, T, — T^ in equation (11) 

 or (12) is zero and no heat flows. This condition is accomplished by 

 a series of thermoelectric junctions distributed over inner and outer 



Fig. 3. Schematic diagram of "labyrinth" flow 

 calorimeter of Swietoslawski. 



wall, and facilities to heat or cool the outer wall so that the galvanom- 

 eter connected with the thermopiles shows no potential difference. 

 This system was invented by Rosa and applied in the famous respira- 

 tion calorimeter for human beings of Atwater and Rosa {23) (Fig. 4) 

 and that for cattle built by Armsby and Fries {3). 



Prevention of heat leaks is particularly important for microcalorim- 

 etry, which would hardly be possible without the very good insula- 

 tion provided by Dewar vessels. Adiabatic jackets are also used in 

 microcalorimetry. A most ingenious device for reducing heat leak- 



