tJie Kledrical J Jiscluirae from a J\)int to a Plane. 623 



The iiietiils pin[)loyed were Pt, Ag, Ou, Ni, Al, Mg, Carbon, 

 and Sodium Amalgam. AH these without exception gave 

 the same effects. Out of 32 experiments^ 6 were irregular, 

 the remainder crii\e : — 



o 



1J 



Positive discharge — Fo^rs for — between 1'253 and 1*247. 



° "^ Vi 



Negative discharge — Fogs for ^ between 1*24:4 and 1*239. 

 ft o o ^^ 



yitropen. — Prepared from air by passing over KOH and 

 red-hot copper. Points of Pt, Cu, Al, Mg, were used — with 

 the same result in every case. 15 experiments, 4 irregular. 



Positive discharge— Fogs for - between 1-252 and 1*251. 



Negative discharge — Fogs for — between 1*251 and 1*250. 



A few experiments were performed with a Pt point in a 

 mixture of about equal volumes of nitrogen and hydrogen, to 

 try whether the chemical action resulting in the formation 

 of ammonia would produce any effect. The results were the 

 same as for hydrogen. 



Oxygen. — Prepared in three ways : — 



(1) from KMnO,, 



(2) from KCIO3, 



(3) from electrolysed potash. 



The metals employed were Pt, Ag^ Ni, Cu, Al, Mg. 36 ex- 

 periments were performed. With the positive discharge 17 

 of these were irregular ; 19 gave the same results as for air 

 and hydrogen, except wdth a magnesium point. The experi- 

 ments with a positive brush from the latter point, and all the 

 experiments with a negative brush, were perfectly irregular 

 and inconsistent. 



Acetylene^ Coal-Gas^ and Carbon Mono.vide. — Ptand carbon 

 points used. These gases were employed to discover what 

 effect a trace of hydrocarbons might be expected to have on 

 other gases : they also exhibit strong absorption of ultra- 

 violet light, a property which might affect their behaviour in 

 the present experiments. 



It was, however, found that the discharge produced decom- 

 position in the gases, and that a cloud was formed with very 

 slight expansions, sometimes with no expansion at all, the 

 clouds being much denser and totally different in appearance 

 to those in other gases. Similar results were obtained in air 

 mixed with a little beuzoline vapour. . , 



