364 Transactions. — Chemistry. 



that in the absence of the wire its conducting function is 

 discharged by certain parts of the walls of the capillary 

 space." He further says that the chemical action between 

 two liquids separated by a capillary partition is determined 

 mainly by the magnitude of the electro-motive force ; and that 

 the intensity of the electro-capillary current depends upon the 

 chemical attraction between the liquids, and the size of the 

 pores, the diameter of which should be such that all the elec- 

 tricity produced by the contact of the liquids may be utilised 

 for the production of the current. 



Loew objects to this hypothesis, and in the "Journal of 

 Practical Chemistry " says he is of the opinion that all Bec- 

 querel's results may be explained without calling in the aid of 

 electric currents, and he proposes to designate the mode of 

 action by the name of chemosmose. 



Loew supports his opinion by stating that when a crystal 

 of cupric sulphate is immersed for some hours in a solution 

 of potassium sulphide, there will be found under the black 

 crust of cupric sulphide which rapidly forms on the crystal a 

 quantity of metallic copper. He says that when a crust of 

 cupric sulphide is once formed the process of decomposition 

 will go on as before only when the molecular gaps (in the 

 crust) are wide enough to allow of the passage of more mole- 

 cules of potassium sulphide, whilst when the gaps are too 

 small chemosmotic decomposition or electro-capillary action 

 will be produced. The potassium unites with the group SO4, 

 metallic copper being separated, while the sulphur previously 

 combined with the potassium remains outside the crust, form- 

 ing potassium disulphide. In reality he assumes that osmose, 

 as favoured by capillary spaces, supplements the effects of 

 chemical action, and under the influence of the newly-formed 

 power potassium sulphide is decomposed into its elements. 



Now, it is clearly to be seen that both these scientists set a 

 high value upon capillary spaces or minute pores, for they 

 certainly wish to inculcate the idea that these possess the pro- 

 perty of greatly intensifying chemical force — a theory so much 

 at variance with the conclusions I have arrived at that I now 

 propose to show you that these so-termed electro-capillary de- 

 posits of Becquerel and the chemosmotic deposits of Loew are 

 simply the product of chemical action unaided by any other 

 force. 



The affmity of the sulphur of potassium sulphide for the 

 copper of cupric sulphate is so strong that at the moment of 

 combination an electric current is generated sufficiently in- 

 tense to deposit copper from its solution ; a fact which may be 

 easily demonstrated by a slight variation of Becquerel's ap- 

 paratus, so as to exclude the possibility of capillary action 

 being in any way connected with this phenomenon. 



