338 C. Barus — Effect of Temperature and of Moisture 



the corresponding initial radial electric current in the con- 

 denser in arbitrary units, when the potential difference, E^ is 

 about 40 volts and the initial deflection, s , as stated. In both 

 cases the insulation of the condenser in the absence of the air 

 current, is measured for each temperature. This is then 

 deducted and the corrected electrical currents tabulated. In 

 Table IY, on the left, a channeled hard rubber bushing guards 

 (unnecessarily as it afterwards proved) against metallic contact 

 of the core and envelope. In the data on the right this has 

 been removed. The phosphorus in both cases is dried pre- 

 liminarily, as stated, by a current of dry air from the desiccator, 

 entering the condenser first and passing thence over the phos- 

 phorus grid into the atmosphere. The last columns give 

 the currents (ds/dt) /s =i Q /s = i /Q , supposing that initially 

 Q = Q o € -*(t-to) as stated in g n> 



Table IY. — Ionizing activity of dried phosphorus. 



JE = 41 volts. 



s = 13- 







dV/dt = -b'l 



liters/pain. 







6 



ds/dt 



So/So 



e 



ds/dt [ 



io/So 



19*2° 



6 



•09 



25-8° 



7 



10 



18-0 



4 



•06 



21-2 



7 



10 



16-5 



4 



•05 



20*0 



9 



12 



15-0 







•00 



18-8 



9 



12 









17-8 



8 



•12 



16-8 



6 



•08 



16-6 



8 



■11 



18*2 



11 



•15 



15-5 



6 



•08 



19-2 



13 



•18 



14-0 



2 



•03 



20*6 



13 



•18 



13-3 



1 



•91 



22-4 



12 



•16 



Color 



experiments 



made at 



2*7-2 



10 



•14 



13-5° 



(here) show( 



id blue 



33-8 



9 



•12 



equivalent to *8 li 



t./min. 









After 



the color 



experi- 









ments 



, for dV/o 



It — '93 









lit / min. results w 



ere as 



. 





, 



follow 

 14-0 







V 



Channelled hard l 



ubber bush- 



S '. 



4 



•OG 



ing in cond 



enser. 





14-0 



4 



•06 



Bushing removed. 



17. Discussion. — The results of Table IY are shown graph- 

 ically in figures 8 and 9, where the currents (ds/dt) /s are as 

 usual the ordinates. In a general way the character of figures 

 6 and 7 has been preserved, inasmuch as there is maximum 

 ionization at about 20° : but the details of behavior are again 

 different. In the first place the scale of the phenomenon is 

 gradually reduced as the emanating body is repeatedly subject 

 to desiccation. This merely means deficient phosphorus sur- 

 face, as I take it. 



