Influence of Voltaic Currents on the Diffusion of Liquids. 63 



than in the other. Reversed current again, line in tnbe below anode 

 produced immediately. 



Exp. 21.— Lower liqnid a saturated solution of chloride of cobalt, 

 npper one dilute nitric acid 1 to 10. Copions conduction. Two lines 

 soon formed about 2 millims. apart in the liquid of tube below cathode, 

 they merged and formed one concave line. The lower liquid appeared 

 to move in the direction of the current. By reversal of current the 

 line appeared in the tube under the cathode, and the coloured liquid 

 in the tube under anode became diffuse. Previous to the line appear- 

 ing, the surface of lower liquid under the cathode was convex ; when 

 the line first appeared that surface became straight, and when the line 

 was fully developed it was concave. The liquid again appeared to 

 move in the same direction as the current. 



Exp. 22. — A saturated solution of yellow potassic chromate below, 

 and one of 3 ozs. of sodic sulphate in 12 ozs. water above. Conduction 

 free. A line appeared in one minute, in liquid of tube below anode, at 

 the verge of dilute part; a second line also appeared but did not 

 merge into the first ; a third line also came, but did not merge into 

 the next one. The solution in the tube below anode diffused upwards, 

 and that in the other concentrated downwards, so that the mass ap- 

 peared to move in a direction opposite to the current. Reversed the 

 current, similar effects occurred. 



Exp. 23. — Lower liquid a saturated solution of perchlorate of nickel; 

 upper one dilute nitric acid 1 to 10. Conduction moderate. In two 

 minutes the surface beneath cathode became perfectly flat and defi- 

 nite, and then concave. Soon also a second line appeared 5 millims. 

 below the other, with increased colour of solution beneath. The 

 liquid in the other tube became diffused in colour. Reversed current, 

 similar effects occurred after about ten minutes. 



Exp. 24. — Small tubes 16 millims. long and 10'5 millims. bore. 

 Lower liquid 1 volume of sulphuric acid to 2 of water, coloured by 

 litmus ; upper one dilute sulphuric acid 1 in 20, not coloured. Con- 

 duction free. Positive meniscus became a little more definite. No 

 other apparent effect. 



. Exp. 25. — A saturated solution of cupric nitrate beneath and dilute 

 nitric acid above. Moderate conduction (battery weak). A definite 

 line, concave and rising, developed in tube under cathode. Reversed 

 current, similar effect but feebler. 



Exp. 26. — -Lower liquid a saturated solution of sodic carbonate, 

 coloured by litmus ; upper one dilute solution of the same salt, con- 

 sisting of 1 volume of the saturated solution and 12 volumes of water. 

 Peeble conduction. The liquid in tube below anode diffused, that in 

 the other tube did not. Mass of lower liquid did not appear to move 

 in direction of the current, but ascended by diffusion at negative 

 meniscus. No production of a visible line. 



