Manchester Memoirs, Vol. I. (1905), No. 2. 



II. Some Convection Effects in a Heated Tube. 

 By C. H. Burgess, M.Sc 



Received and Read, November 14th, igo^. 



W. C. D. Whetham, in his " Experiments on Ionic 

 Velocities " [F/ul. Trans. A, 1893, 337], half filled a V-tube, 

 of special construction, with a red alcoholic solution of 

 cobalt nitrate. A layer of a specifically lighter blue 

 solution of cobalt chloride in alcohol was placed above it. 



On passing an electric current through the apparatus, 

 a number of purple lines were formed at the junction of 

 the two solutions and the lines travelled both with and 

 against the current. Whetham could explain this behaviour 

 only by the presence of coloured complex anions in the 

 solution. 



During some similar experiments I filled the upper 

 portion of a U-tube with hydrochloric acid and the lower 

 portion with a specifically heavier solution of cobalt 

 chloride in the same acid. After standing overnight the 

 blue liquid had diffused up into the colourless, giving a 

 gradually shaded band. On passing a current of half an 

 ampere through the tube by means of carbon electrodes, 

 the band was resolved into a series of layers of gradated 

 shades, with a sharp line of demarcation between each. 



To determine whether this was due in any way to 

 complex ions, the blue cobalt chloride solution was replaced 

 by hydrochloric acid, to which a red dye and a little 

 glycerine (to render it heavier) had been added. 



After diffusion had taken place the step-like layers 

 were formed by the current. 



December 2 jid, jgOj. 



