. Transactions of the Royal Society of New Zealand. ertainly wish to inculcate the idea that these possess the pro-perty of greatly intensifying chemical force—a theory so muchat variance with the conclusions I have arrived at that I nowpropose to show you that these so-termed electro-capillary de-posits of Becquerel and the chemosmotic deposits of Loew aresimply the product of chemical action unaided by any otherforce. The affinity of the sulphur of potassium sulphide for thecopper of cupric sulphate is so strong that at the moment ofcombination an electric current is generated sufficiently i
. Transactions of the Royal Society of New Zealand. ertainly wish to inculcate the idea that these possess the pro-perty of greatly intensifying chemical force—a theory so muchat variance with the conclusions I have arrived at that I nowpropose to show you that these so-termed electro-capillary de-posits of Becquerel and the chemosmotic deposits of Loew aresimply the product of chemical action unaided by any otherforce. The affinity of the sulphur of potassium sulphide for thecopper of cupric sulphate is so strong that at the moment ofcombination an electric current is generated sufficiently in-tense to deposit copper from its solution ; a fact which may beeasily demonstrated by a slight variation of Becquerels ap-paratus, so as to exclude the possibility of capillary actionbeing in any way connected with this phenomenon. Skey.—Fallacy of the Electro-capillary Theory. 365 Solutions of potassium sulphide and cupric sulphate areconnected by two siphons filled with a solution of sodicchloride, as shown in the accompanying diagram :—. A. Potassium sulphide. B. Sodic chloride. C. Cupric sulphate. In the solution of potassium sulphide a plate of sulphurisedplatinum, galena, or covelline is placed, and this is connectedwith a platinum electrode placed in the cupric sulphate. Ina short time it will be found that the platinum which has con-tact with the cupric salt is covered with metallic copper, andit may be observed that this effect is produced before any filmor precipitate of cupric sulphide or any other compound hasformed. Clearly, then, in this instance no portion of the effectis due to capillary or osmotic force. In Becquerels so-called electro-capillary apparatus whatreally takes place is this : The first action is the formation ofsulphide of copper in that part of the fissure joining the twosolutions which is contiguous to the potassium sulphide. Thisblocks the fissure at that point, cuts it off from the sulphide,and produces a measure of electric force—in f
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