THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOUENAL OF SCIENCE. 



SUPPLEMENT to VOL. II. FILTH SEEIES. 



LX. On Electricity disengaged between Mercury Surfaces; 

 and on the Motions produced in Mercury by JDeoxidation. 

 By Robert Sabine*. 



IN the spring of last year the late Sir C. Wheatstone had 

 his attention directed to Erman's discovery, that a glo- 

 bule of mercury in contact Avith an electrolytic liquid within a 

 tube of small calibre moved forward when a current of elec- 

 tricity was passed through itf. Taking advantage of this 

 motion, Sir Charles invented a novel form of telegraph receiv- 

 ing-instrument which he described in a patent % taken out in 

 the autumn, and in making experiments upon which he was 

 engaged in France at the time of his death. 



As one of his executors, the duty devolved upon me of as- 

 certaining how far this novel telegraphic instrument could 

 be made available for actual work ; and to this end I found it 

 necessary to undertake a series of preliminary experiments in 

 order to obtain a better knowledge of the principles which 

 underlie the phenomenon. Such an inquiry Sir Charles had 

 in contemplation, and would, I believe, have carried out after 

 his return to England. I shall shortly give an account of the 

 performance of different forms of this receiver ; but before 

 doing so, I propose, in the following pages, to submit the expe- 

 riments I have made, and which have not only revealed phe- 

 nomena not observed before, but have suggested some expla- 

 nations different from those offered by experimenters on the 

 electrical behaviour of mercury. 



A preliminary series of experiments led me to conclude 

 that every mercurial surface, when exposed to the influence 

 of air or water, consists of mercurous oxide and not 

 of metallic mercury, that the electropositive condition of a 



* Communicated by the Author. 



t Erman, Gilb. Ann. vol. xxxii. (1809), p. 2G1. 



\ No. 2771, dated Aug. 5, 1875. 



Phil Mag. S. 5. No. 14. Suppl, Yob 2. 2 1 



