SELIG HECHT 



removed, jacketed with the rubber tubing, and compared with the 

 standards. 



Readings are usually made to the nearest 5 per cent concentration. 

 The reading is thus, say, 70 or 75 per cent. Occasionally, however, it is 

 so clear that the color is nearly but not quite one of the 10 per cent 

 tubes, that the reading is given between the 5 and the 10 per cent 



lOO 



I 

 I 

 § 



eo 



60 



^o 



zo 





O /O ZO 30 4-0 



Fig. 2. The results of Experiment 80. Light intensity is 53 meter candles. 

 The monomolecular nature of the bleaching process is evident from the coinci- 

 dence of the experimental points (rectangles) with the curve calculated on the 

 assumption that ^=0.034. 



steps; for example, 48 or 52. This happens comparatively infre- 

 quently. 



After a colorimetric determination the jacket of the tube is removed, 

 the tube replaced, and the exposure renewed. After a sufficient ex- 

 posure, the tube is again removed, and its concentration again deter- 

 mined. The process is repeated until the bleaching is complete. 



