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ROYAL SOCIETY OF CANADA 



42. ^ Other sets, taken at this time, clearly indicate that when the 

 eyes are simply exposed to coloured light (readings being taken at the 

 beginning and end of one minute exposures) the periodicity does not 

 increase nearly so rapidly as when an object is " fixed " through the 

 coloured glasses and observations are taken in quick succession. In 

 such dase, as before, where the readings were uninfluenced by readings 

 with other glasses, the oscillations were quicker for I B than they were 

 for E. 



43. The numerical data for the sets just referred to are as 

 follows : — 



44. In all of the foregoing experiments no idea can be gained of 

 the periodicity corresponding to G, for undoubtedly the " fixing " of 

 the eyes for other colours makes the oscillations slower (when the plates 

 are used in quick succession) for the observations that follow, and in 



