564 BEPORT — 1891. 



but about 2', and that in the direction opposite to what is found for an ordinary 

 surface. This 2' can hardly be other than real, for it has been recovered several 

 times after complete resetting of all the apparatus. 



In any case the ellipticity here presenting itself is exceedingly small. We have 



/c= + tan 30° tan 1'= + -00017. 



The intensity of the light reflected from water at the polarising angle, measured by 

 K^, is not more than about yoVtj of that found by Jamin. Alcohol is not nearly so 

 dependent as water upon the methods for freeing its surface from contamination ; 

 but, on the other hand, I was unable to apply these metJiods so completely. The 

 value obtained was 



K= + -00085. 



A strong brine, cleansed like the water, gave 



K= --00042. 



About the same value applies to a saturated solution of camphor, while fur oleate 

 of soda the value was —■002. For petroleum again k= + -0010. 



It is impossible to feel confidence that these small values really express pro- 

 perties of the liquids whose names are attached to them. What is certain is that, 

 in a large number of cases, the ellipticity is very much less than has hitherto been 

 supposed, and it is not improbable that even the residual ellipticity may be due 

 to contamination, or, if not to contamination properly so-called, to iusuthcient 

 abruptness in the transition from the one medium to the other. 



SATURDAY, AUGUST 22. 

 The following Reports and Papers were read : — 



Depaktment I. — Physics. 

 1. Sixth Report of th? Committee on Electrolysis. — See Repoits, p. 122. 



2. Interim Report on the Present State of our Knowledge in Electrolysis and 

 Elect ro- Ch em istry. 

 Mr. W. N. Shaw was not able to present a Report this j'ear. 



3. Electrolytic Problems. By Robert L. Mond. 



The author establishes the complete analogy between electric conduction 

 through electrolytes and what may be called metallic conduction. 



He assumes with Wiedemann that the better conducting molecules in the 

 electrolyte form chains, while the worse conducting molecules lorm dielectric tubes 

 surrounding them. According to Clerk Maxwells theory, electric energy is trans- 

 mitted through the dielectric along conductors. The author assumes that this 

 transmission is accompanied by molecular dissociation in the dielectric tubes sur- 

 rounding each electrolytic chain. A\'ith these assumptions he explains the chief 

 electrical and chemical effects produced during electrolysis. 



The author gives an account of experiments he has made to test the validity of 

 the above views. 



4. On Clausius' Theory of Electrolytic Conduction, and on some Secret 

 Evidence for the Dissociation Theory of Electrolysis.^ By J. BnowN. 



' See the Report of the Committee on Electro!} sis, p. 122. 



