On Flames containing Vaporised Salts. 147 



was measured with a view to subsequent experiments, and was found 

 to be with a half-normal solution five or six times as great as that 

 of the vastly more concentrated water vapour which existed in the 

 flame. 



11. Experiments with Decolorised Flames containing Salt-Vapours. 



When chloroform vapour is passed into a flame containing a salt- 

 vapour, the colour is suppressed, owing to the large amount of hydro- 

 chloric acid formed. The conductivity of flames in this condition was 

 determined and compared as nearly as was possible with the con- 

 ductivity of flames containing the same amount of vapour, but no 

 chloroform. The salts of lithium, potassium, and caesium were used. 

 It was found that the conductivity of the flames was not largely 

 affected by the decolorisation. With small E.M.F.'s the conductivity 

 was somewhat diminished, but with an E.M.F. of 5*6 volts an increase 

 was always noticed. 



12. Conductivity of Salts vaporised in the Flame of Cyanogen. 



The view of Arrhenius is that salts are hydrolysed in flames by the 

 water vapour present, and that the hydrate furnishes the ions. To gain 

 some idea of the influence of water vapour, the cyanogen flame was 

 chosen as a medium for the volatilisation of salts. Such a flame con- 

 tains only the water coming from the sprayer. No differences were 

 noticed in the behaviour of the several salts that would not have been 

 found equally in a coal-gas flame. 



The high general temperature reigning in a cyanogen flame causes a 

 high degree of conductivity. A dry salt vaporised into a cyanogen 

 flame from a platinum wire shows great conductivity, and thus it seems 

 certain that the presence of water vapour in the flame is not necessary 

 for the production of ions. 



General Conclusions. 



1. The authors conclude from their experiments, that the conduc- 

 tivity of vaporised salt is of an electrolytic character, but that there are 

 features connected with it that distinguish it from electrolytic conduc- 

 tion in aqueous solution. Thus Ohm's law is only obeyed within certain 

 limits, and the general relation between current strength and electro- 

 motive force can only be represented generally by a more complex 

 expression. 



2. The conductivities of different salts differ greatly, according to 

 the electropositive constituent. 



3. Among different salts of the same metal differences of conductivity 

 VOL. LXIV. N 



