. Studies in physics. type A. The sensibility in the blue end of the spectrum decreasesmarkedly while in the red it is hardly affected. At the highest tempera-ture reached, however, there is no indication of an appearance of a maxi-mum in the red, as might be expected, perhaps, as a result of the de-pression in the blue. Unfortunately, while trying to raise the tempera- AP. 33. W O— 230C; 309000 Ohms; Volts; 10 aeo. O— 137°C; 30000 Ohme; 13 Volta) 10 eeo. 3x / 0-9-S. ,/ ^4 500 ido X In pp Fig. 4. ture of this cell to somewhere near the melting point of selenium, theselenium melted and
. Studies in physics. type A. The sensibility in the blue end of the spectrum decreasesmarkedly while in the red it is hardly affected. At the highest tempera-ture reached, however, there is no indication of an appearance of a maxi-mum in the red, as might be expected, perhaps, as a result of the de-pression in the blue. Unfortunately, while trying to raise the tempera- AP. 33. W O— 230C; 309000 Ohms; Volts; 10 aeo. O— 137°C; 30000 Ohme; 13 Volta) 10 eeo. 3x / 0-9-S. ,/ ^4 500 ido X In pp Fig. 4. ture of this cell to somewhere near the melting point of selenium, theselenium melted and the identity of the cell was thereby destroyed. 1 Phys. Rev., Series II., Vol. IV., p. 48, 1914- i94 E. 0. DIETERICH. [SecondLSkries. From the behavior of cells of type A, one would be led to expect thatin the case of cells with a maximum in the red, this maximum should bedisplaced towards the longer wave lengths. This was actually found tobe the case. Figs. 4 and 5 show the progressive change of the position A R. soo 600 800 X in nn Fig. 5. of maximum sensibility with increasing temperature. These results are in perfect agreement with those of Elliott1 who finds the maximum shifted towards the shorter wave lengths at the temperature of liquid air. Fig. 6 shows that the characteristic wave-length-sensibility curve at AR. c O A( c B X y - \ 0 _ A —B- HoBefoi . 33. ?e heating \. ,0-^ -0-^ > 0 < 33° te]33° 309000 0* Jolie; 10 t • heating; 76000 01 folte; 10 1 me; 60. ma;eo. 600 800 X In pH Fig. 6. room temperature is not changed by the heat treatment; the maximumreturns to the original place. The difference in resistance and sen-sitiveness before and after heating may probably be due to slow changestaking place in the selenium similar to those exhibited by the freshlymanufactured cells. Physical Laboratory, The State University of Iowa. 1 Phys. Rev., Series II., Vol. V., p. 53, 1915. Reprinted from The Physical Review, N. S., Vol. VIII. No. 5, November,
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