a Conducting Liquid electrified in Mercury. 197 



axis, keeping up a constant circulation ; and that an increased 

 capillary attraction has absolutely nothing to do with it. 



The most interesting part of Professor Erman's paper is his 

 account of the circulation which takes place in mercury when 

 electrified in contact with conducting fluids. He has seen and 

 described the circulation of mercury under sulphuric acid, and 

 carbonate of potash ; and has thus undoubtedly anticipated 

 much that I believed new in my investigations. 



His account of these pheno'mena (which he calls galvanic 

 figures) he concludes with this remark, that " These pheno- 

 mena incontestably originate in an increase of cohesive attrac- 

 tion of the two fluids." An increased cohesive attraction be- 

 tween two fluids will make them adhere more firmly to each 

 other ; it will alter, while it lasts, the figure of equilibrium of 

 their common surface ; but it is contrary to every principle of 

 mechanics to attribute to it regular, continued, violent, and 

 extensive internal motions, and a subversion of all equili- 

 brium. 



So far Professor Erman. It will readily be seen by the 

 foregoing sketch, how far his researches extend. Whatever 

 we may think of his theory, two leading facts, that regular 

 and constant motions arise in fluids under the influence of the 

 Voltaic current passing over mercury, and that these motions 

 vary with the nature of the fluids, are certainly his discovery, 

 and I most gladly yield him the priority. Every thing be- 

 yond this in my Bakerian Lecture, — the minute analysis of 

 the phenomenon, the influence of variations in the electro-che- 

 mical nature of the fluid, — the intense effect of alloys of almost 

 infinitesimal portions of the electro-positive metals present in 

 the mercury, and the comparative inertness of the electro-ne- 

 gative ones, — the explanation of the complicated anomalies 

 presented in these delicate experiments, — and the reference to 

 one general fact, of the innumerable minute and enigmatical 

 phenomena observed both by myself, and by M. Serrulas in 

 his very curious papers in the Journal de Physique, on the 

 rotatory motions assumed by the alloys of potassium when 

 floated on mercury under water, — I think I may fairly claim. 

 The subject is certainly of the highest interest, and merits 

 every attention from the electro-chemical philosopher; and 



m 



