500 
ME. H. A. AVILSON ON THE ELECTRICAL CONDUCTIAMTY 
(1.) Description of the apparatus for producing the flame. 
(2.) The relation between the current and E.M.F. in the flame. 
(3.) The fall of potential between the electrodes. 
(4.) The ionisation of the salt vapour. 
(5.) The relative velocities of the ions in the flame. 
(G.) The relative velocities of the ions in hot air. 
(7.) Conclusion. 
A summary of the earlier work done on this subject is given in Wiedemann’s 
‘ Lehre von der Elektricitiit,’ vol. 4 B. Arrhenius’s paper (‘Wied. Ann.,’ vol. 42, 
1891) is referred to in our paper mentioned above. 
(1.) Descrii^tion of the Apparatus used for Producing the Flame. 
The apparatus used for producing the flame was similar in principle to that used in 
the investigation referred to above. Carefully regulated sujiplies of coal gas and air 
were mixed together, along with spray of salt solution, and the mixture burnt from a 
brass tube, 07 centim. in diameter. The apparatus is shown in flg. 1. 
P, AA^ater pump. 
INI M', AA^ater manometers. 
E, Exit tube from G. 
B, Mercmy 
R, Gas regulator. 
G', Second globe. 
A, Carboy. 
H, Gasometer. 
F, Flame. 
AA^, AA^ater flask. 
L, Constriction. 
D, AAMod block. 
S, Gouy sprayer. 
G, Globe containing salt solution. 
The air supplied by the water pump, P, jiartly escapes by bubbling through mercury 
in B, and then passes into a carboy, A. From A the air passes through a flask, W, 
containing water, to the Gouy sprayer, S, and its pressure is measured by the water 
inamometer, M. The air supply is regulated b}^ means of a pinch-cock, K, and by 
