RELATIVE STIMULATING EFFICIENCY OF LIGHT 



165 



TABLE 6 



Relation between stimulating efficiency and the ratio between the duration of the 

 flashes and the dark periods between the flashes, as ascertained by an analysis of 

 the data given in table 5. Lights of the same flash-frequency are arranged in groups . 

 "y," arbitrary unit, amount of light energy emitted in a single flash of intermit- 

 tent light of flash-frequency of SO per second produced by rotating disk with one- 

 fourth removed 



It is probable that tests of larger numbers of butterflies would 

 change the relative stimulating efficiency assigned to several 

 of the lights. 



Table 6 shows that the differences in illumination of the various 

 lights used does not cause the differences in stimulating efficiency 

 of these lights, for lights differing greatly in the amount of light 



