Page:Collected Physical Papers.djvu/265

Rh Self-Recovering Receiver

It has been shown that receivers which exhibit a diminution of resistance under electric radiation give a characteristic curve which is concave to the axis representing the current, and that in the non-recovering type noticed hitherto, the forward and return curves do not coincide, but enclose an area. I was now interested in finding out what would be the peculiarities of the characteristic curve of receivers showing self-recovery.

I have, as previously mentioned, described a self-recovering receiver of the negative type, made of silver particles. I also succeeded in constructing a self-recovering single point receiver of the positive type,

the successive responses of which to brief flashes of radiation are given in figure 56.

In working with receivers which have been at rest for long periods it is often noticed that the response is at first feeble. The sensitiveness soon improves, and may even become excessive; it finally settles down to a