162 



Prof. J. C. Bose. On the Continuity of [Apr. 18, 



5. A Self-recovering and Metrical Receiver. 



But the most perfect type of self-recovering receiver that I have 

 succeeded in constructing was made of the strained variety of silver 

 described in my previous paper. I there showed that this variety of 

 silver exhibits, under the action of radiation, an increase of resistance. 

 I had with me a portion of this variety prepared more than a* year 

 ago, and it is probable that time had improved its quality. I made 

 with it a receiver by having about 3 mm. thickness of the powder 

 between two electrodes, one of which, by means of a micrometer 

 screw, could be made to produce a gradual compression. The applied 

 electromotive force was 0'4 volt, and the resistance of the receiver 

 was equal to 20 ohms. The receiver showed the usual increase of 

 resistance at first, with a tendency to self-recovery. In about half an 

 hour it began to exhibit the most perfect self-recovery, and for the 

 next 3 hours of continuous work it went on giving an extraordinary 

 consistency of response. 



A short rod was the source of radiation throughout these experi- 

 ments. The intensity of incident radiation was varied by changing 

 the distance of the radiator. In fig. 4 are given responses to indi- 

 vidual flashes at distances of 40 and 15 cm. It will be seen that the 







































































1 



a) 











































































y 



y 





h 











h 



> s 



V 



































Time of Exposure. 



Fig. 4. — Transient increase of resistance in an Ag' receiver due to single flashes of 

 radiation. In (a) the radiator was at a distance of 40 cm. ; in (b) the 

 distance was 15 cm. Thick lines represent the effect of radiation, thin lines 

 represent the recovery. 



effects are very consistent, the occasional variation being probably due 

 to certain oscillatory sparks not having been as efficient as the others. 



Certain Analogies with the Phenomena of Phosphorescence and Thermo- 



