470 C. FE. Fritts—New Form of Selenium Cell. 
other day, no effect was produced, although the conditions were 
the same, so far as I could detect. 
Experiment 2. Double cell No. 1, measured 50,000 ohms. 
Put on an automatic reversing apparatus (arranged to both 
break circuit and reverse the current about 300 times per 
minute), with 22 cells of Leclanché, for three minutes. The 
cell then measured, under the same conditions as before, only 
30,000 ohms. A repetition of this treatment produced no 
" further effect. The change, produced as described, was perma- 
nent. 
The action of both intermittent and alternating currents 
upon selenium are worthy of careful study, for under certain 
conditions they are capable of effecting great changes in its 
resistance, which might be utilized for practical purposes if 
those conditions were understood. so 
5th. Very moderate changes of temperature (say 10° to 50 
Fahr.), can sometimes change the resistance of a selenium cell 
hundreds or even thousands of ohms in a few seconds, an 
think that this phenomenon has not been observed by others. 
Experiment 1. Brass cell No. 6 measured, with gold anode, 
23 cells Leclanché, in dark, 3,500 ohms. It was laid with its 
back upon an iron block warmed to about 100° Fahr., when its 
resistance fell almost instantly to 2,900 ohms, being a fall of 
600 ohms. ; 
Experiment 2. The same cell, in the same conditions at an- 
other time, measured 8,600 ohms. On putting the hot block — 
under it, it fell to 2,400 ohms; in 30 seconds more it fell to 
2,000 ohms; in another 80 seconds, to 1,850 ohms; in two 
minutes more to 1,600 ohms. By this time the block was but 
slightly warm. 
Experiment 8. A cold block (i. e., not heated), was then put 
under the cell, when it rose at once to 1,920 ohms; in 30 sec- 
onds more, to 2,000 ohms; and continued to rise rapidly to 
3,010 ohms. On repeating experiments 2 and 3, similar results 
stantly, and that the withdrawal of so little heat can produce @ 
change in the opposite direction, almost as great and a 
is one of some importance, and has not been published before, - 
e ; ae 
so far as I am aware. 
