370 



0. U. VONWILLER. 



Fig. 3. 



It is seen that the rise is relatively most rapid with the 

 most intense light, the maximum value being attained first 

 with the light at 100 centimetres. With the green light, 

 however the curve of rise differs considerably from those 

 obtained with red light ; the fraction of the total increase 

 attained during the first half minute is greater than that 

 with the red light at 300 centimetres, but is decidedly less 

 for the first minute, the difference increasing with the time 

 until at five minutes the rise for the green is practically 

 the same as that obtained with the red at 600. 



In fig. 4 curves are drawn illustrating the recovery of 

 the cell after the cessation of the illumination ; the 

 abscissas represent times and the ordinates give the 

 fractions still remaining of the total change produced by 

 the light. Curves are drawn for the same cases as in 

 fig. 3 and in addition that for the more intense green light 

 (observation 6, Table II). A is the curve for red light at 



