1881.] caused by Liquid Diffusion and Osmose. 299 



diaphragm and no diaphragm would also give rise to an electric 

 current, I charged the whole of the thirty-five glass cups with the 

 acidulated strong solution of cupric sulphate employed in the last 

 experiment, and rilled all tbe connecting tubes with the weaker solu- 

 tion used in that experiment, taking care to alternate the ends of the 

 tubes which were open with those which were closed by a septum, as 

 in the annexed sketch (fig. 2) . I also employed as electrodes, moveable 



Fig. 2. 



platinum wire of much larger surface, cut from contiguous portions 

 of the same piece of wire and insulated at their upper parts from the 

 liquid by means of glass tubing. By this arrangement a much 

 stronger electric current was produced than in the previous experi- 

 ments ; but in a reverse direction, viz., from the strong solution up- 

 wards through the diaphragm into the weak one, and from the weak 

 one down through the meniscus into the strong one. 



Experiment 4. — A similar experiment to IS o. 3 was now made with 

 a nearly saturated solution of potassic nitrate and a mixture of half a 

 drachm of that solution with 34 oz. of water. The current was the 

 same in direction as in the last experiment, but more feeble ; and was 

 strongest at the first contact. 



Experiments 5 and 6. — These experiments were similar to No. 4, 

 except that (with the hope of obtaining a stronger effect) the whole 

 of the bent tubes were filled with the solution previous to placing 

 their ends in the vessels ;* the strengths of the solution of saltpetre 

 were also somewhat different. The currents obtained were the same 

 in direction and magnitude as in Experiment No. 4. 



Remarks. — In all these four last experiments, the electric currents 

 produced by the difference of osmose caused by a porous partition, 

 were upwards through the diaphragms and opposite in direction to 

 those produced in Experiments Nos. 1 and 2 by difference of diffusion. 



I have since obtained very much stronger currents, sufficient to 

 readily send the image off the scale, by means of even a single diffusio- 

 electric element. 



* Henceforth the whole of the tubes were always filled previous to immersion. 



