VI. 



C A LORI METRIC MEASUREMENTS 



199 



plislied, to a certain extent, by the so-called Kata thermometer de- 

 signed to nieasiu-e the cooling power of various environments. A 

 short historical account of this instrument, with the description of a 

 new form, the thermointegrator, is given by Winslow and Greenburg 

 (.31). 



A simple form of Kata thermometer is shown in Figure 6A. It is 

 a thermometer wth two temperatures, ti and /2, marked on its stem. 



O 



A. 



Fig, 6. Schematic sectional diagrams of two 

 types of Kata thermometer. 



The instrument is first heated above its upper temperature and the 

 time required to cool it from ^i to ^2 is measured with a stop watch. 

 The cooling power of the environment is an inverse function of that 

 cooling time. 



Another type of Kata thermometer measures the heat necessary 

 to maintain the temperature of a test body at a given level. Figure 

 6B shows an instrument of this type. The test body, H, contains 

 two spirals of enameled copper wire, Cu, which are connected to two 

 spirals of manganin wire, Mn, to form a Wheatstone bridge supplied 

 by an electric current from the battery, B. The resistances are 

 adjusted so that the bridge is in equilibrium, indicated by a null 



