58 



EXPERUrENl'S Wmi IONIZED AIR. 



made out. Usually not more than a few per cent, of the emanation will pass even 

 under favorable conditions. The large values found for writing and tissue papers 

 were not again obtained in many sui)sei[uent e.vperimeuts except in a single instance. 

 They may be errors, though carefid inspection of the results revealed none. It is 

 also possible that the emanation from phosphorus may be different in quality under 

 qualitatively different circumstances a|>art from intensity. 



The general result obtained is thus definitely against any obscure radiation. 

 The emanation passes with great difficulty and loss in quasi-gaseous form even 

 through very tliin poious barriers. It is stopped by impervious media, however 

 thin. Oiled tissue paper cuts off the ions unconditionally. Negative leakages are 

 sometimes observed with such l)arriers as celluloid, due no doubt to static charges 

 produced by friction. One is also easily misled by conduction. 



17. Effect of temperature, etc. — It was thought that temperature might possibly 

 have some discriminating influence on the charge in relation to its tendency to pass 

 through paper. The following experiments were made at low temperatures with 

 this quest in view. 



T.\BLE 12.— TRAXS.MISSION AT LOW TEMPERATURES, 6 = ,2°. 



No effect is detected. 



The folltiwing expcriment.s, tal)le 13, sliow curious incipient i)erraeabilities' 

 decreasing in the lapse of time, afterwards to be regained. Tlie large values for 

 tissue paper and larger values for filter paper (c' = .<•.") to .(it;) have tlius again 

 been ol)tained under trustworthy conditions. Cliange of the sign of the diarge is 

 without effect. 



' In recent experiments I have demonstrated the penetrating potency of moist phosphorus 

 emanations. 



