194 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



the heated pipe showed a slight tendency to move away from it, but 

 beyond twenty centimeters they were apparently indifferent. 



The amount of heat given off by the steam pipe as compared to that 

 given off by the light apparatus was determined by means of a pair of 

 thermometers. These thermometers were mounted in a wooden box 

 (Figure 7), blackened inside and out and divided into two freely com- 



TABLE XVII. 

 Reactions of Fouk Eyeless Toads to Light and to Radiant Heat. 



municating compartments in each of which the blackened bulb of one 

 of the thermometers (A, B) was enclosed. One of these compart- 

 ments was permanently closed, while the other could be opened or 

 closed at will by a slide (d). This apparatus was placed in such a 

 position that the radiant heat to be measured fell directly upon the 

 bulb of the thermometer B when the slide was out. After reading 

 the thermometers at intervals and allowing the apparatus to become 

 adjusted to the surroundings for two hours, the difference between the 

 two thermometers was observed at one-minute intervals for twenty 

 minutes while the compartment was open to receive the light or heat 

 to be tested, and then for a like period of time with it closed. The 



