440 Mr. Garrett and Dr. Willows: Chemical 
a charging up took place. This might easily be due to the | 
projection of solid particles of iodine. The plate with its | 
mixture could be used after standing for several days, when 
on heating, and without the addition of fresh iodine, the 
same behaviour was observed. 
Time to leak through | 
Metal. Charge. B dicinenel | Temperature. 
——— | SS SS 
) min. sec. | 6 
Copper | Negative ‘Wi .uc/2.c0: | ly ae | 20 
a ‘ / Le | 185 
1° 2a ) 236 
1 ao 256 
| 1 5 / 272 
1 0 286 
| 45 291 
! 45 293 
/ 40 300 
| | 27 | 802 
| 15 307 
These are results of the same order as for zine plates. 
Only a small leak was obtained with a positive charge. It 
is noticeable that the temperature at which the leakage | begins 
is higher wick popper than with zine. 
| 
| on Time to leak through 
Metal. Charge. 5 divisions: | ‘Temperature. 
min. sec. ° 
Brass...| Nepative ............ | 5 ee | 22 
| 2: * 2S 225 
3 0 260 
| 2 20 279 
! 1 20 . 290 
lL ag 296 
] 0 | 305 
With a positive aoe ge a small leak was obtained. The 
observations show that the effects are not so great with brass 
as with copper and zinc. 
| | | 
| 
+ve | No leak. 
| Metal. Charge. | Result on heating. 
| =. aes —otoeeas| ae 
| Aluniminm,........... —ve | Practically no increased leak. 
+ve | Practically no increased leak. 
| Asin eee ee coos | —ve | No increased leak. 
+ve | No increased leak. 
Timed irom %....--:. —ve | Increased leak. 
| +ve | Scarcely any increased leak. 
| Platinum; 2702... —ve | No leak. 
| 
