256 



Experiments on Electric Osmose. [Dec, 16, 



the most diverse solutions, viz., in acids, alkalies, neutral salts, aqueous 

 and alcoholic liquids, concentrated and dilute solutions, &c, we might 

 be apt to infer that the chemical composition of the electrolyte had no 

 influence upon it ; but as a single exceptional instance will overturn 

 the widest generalisation, so the exceptional behaviour of a solution of 

 bromide of barium in absolute alcohol invalidates the conclusion that 

 the direction of flow of liquids in electric osmose, is independent of the 

 chemical composition and molecular structure of the liquid. The 

 danger of drawing conclusions from too limited a number of instances 

 is well illustrated in this case, especially when we further remember 

 that it is the exceptional instances which usually disclose the widest 

 truths. 



As the exceptions formed a very small proportion of the whole 

 number of examples, it would appear that the direction of the flow 

 depended very much more frequently upon the direction of the electric 

 current than upon the internal architecture of the liquid. 



In order to be able to compare the direction of motion of the mass 

 of the liquids, produced by passing an electric current from a heavier 

 to a lighter liquid lying upon it without a separating diaphragm, in 

 the research already referred to, with that produced when the liquids 

 were separated by a vertical diaphragm, additional experiments were 

 made. The osmose cells employed in these experiments were about 

 4*7 centims. high, 2*5 centims. long, and about 2*0 centims. wide at 

 right angles to the diaphragm ; and the diaphragms were cemented in 

 with sealing-wax. 



Experiment 1. — Current from 26 Grove's cells in single series, passed 

 from a saturated solution of sodic sulphate to a one-fourth saturated 

 one of potassic chloride. Osmose occurred in the direction of the 

 current. 



Experiment 2. — Current passed from a mixture of 1 volume of sul- 

 phuric acid and 7 of water to one composed of 5 volumes of a satu- 

 rated solution of oxalic acid, and 3 of water. Osmose produced in the 

 usual direction. 



Experiment 3. — Current passed from a strong solution of potassic 

 chloride to a mixture of 1 volume of a saturated one of ammonic 

 sulphate and 3 volumes of water. Rapid osmose took place in the 

 ordinary direction. 



Experiment 4. — Current from 5 Grrove's cells in single series, passed 

 from a solution composed of 1 volume of a concentrated solution of 

 sodic hydrate and 3 volumes of water, to a saturated one of sodic car- 

 bonate. Osmose occurred in the usual direction. 



Experiment 5. — The same current, passed from a strong solution of 

 amnionic nitrate to one of 1 volume of a saturated solution of sodic 

 carbonate and 3 volumes of water. Feeble osmose in the ordinary 

 direction took place- 



