Electrical and Chemical Properties of Stannic Chloride. 383 



I wish to add that Mr. A. W. Price has greatly assisted 

 me in the manufacture of the new instrument. The method 

 of increasing the velocity of the carriage by the introduction 

 of a pulley attached to the driving-weight is due to him. 



XLII. On the Electrical and. Chemical Properties of Stannic 

 Chloride ; together with the Bearing of the Results therein 

 obtained on the Problems of Electrolytic Conduction and 

 Chemical Action. — Part I. Experimental Observations. 

 Part II. Theoretical Considerations. By Ward Coldridge, 

 B A., Scholar of Emmanuel College, Cambridge* . 



Introduction. 



THE germ from which this work has been developed was 

 found in Faraday's statement that Stannic Chloride is 

 a nonconductor. In the first instance this led to an investi- 

 gation of the lower- limit of its conductivity ; the result which 

 is here recorded was submitted to the Meeting of the British 

 Association at Bath in 1888 by my friend Mr. W. N. Shaw, 

 Fellow of Emmanuel College, who experimented with me on 

 this point : in the second instance I examined the condition 

 requisite for the development of electrolytic power; the 

 results obtained are here for the first time recorded. 



It is claimed that, by taking advantage of the suitable 

 chemical and physical properties of stannic chloride, a defi- 

 nite advance has been made towards the resolution of the 

 ambiguous statement that " heterogeneity is necessary for the 

 development of electrolytic power," and that the results of 

 Part I. throw light on the nature of an effective impurity, 

 and in so striking a manner exhibit the parallelism between 

 the chemical and electrical properties that the conviction 

 arises of an ultimate explanation common to both. I have 

 endeavoured to arrive at a single consistent view which shall 

 explain the phenomena observed ; and in stating the idea I 

 have carefully abstained from wandering into disquisitions on 

 other ideas, as that of Arrhenius's vagrant atoms, which, 

 according to my notion of the stability of the fundamental 

 chemical molecule, are untenable. 



The field of research from which these results have been 

 gathered is a fertile one. Incidentally some opportunities 

 are mentioned : I am conscious that pure pentachloride of 

 antimony, inter alia, would yield interesting results. 



With much pleasure I acknowledge my indebtedness to 



* Communicated by the Author 



