Note on a simple form of Lippmann's capillary electrometer useful to physiologists / by Professor John G. M'Kendrick, M.D.

  • McKendrick, John G. (John Gray), 1841-1926.
Date:
[1883?]
Catalogue details

Licence: Public Domain Mark

Credit: Note on a simple form of Lippmann's capillary electrometer useful to physiologists / by Professor John G. M'Kendrick, M.D. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    NOTE ON A SIMPLE FORM OF LIPPMANN’S CAPIL- LARY ELECTROMETER USEFUL TO PHYSIOLO- GISTS.1 By Professor John G. M‘Kendrick, M.D. The action of the substances set free on the electrodes in electro- lytic decomposition, and the energy shown as motion in these circumstances, is strikingly manifested by the behaviour of a drop of mercury in dilute sulphuric acid, when the positive pole of a battery is put in connection wTith the mercury, and the negative pole dips into the acid. The mercury extends towards the negative electrode during the passage of the current, becom- ing covered with a film of sub-oxide, which dissolves in the acid, leaving a bright surface. By making and breaking the current a series of oscillations is set up. Movements in the mercurial electrode and adjacent acid have been observed by Henry, Gerboin, Erman, J. F. W. Herschel, Draper, Paalzow, Faraday, and Quincke,2 and they received various explanations. Erman,3 in 1809, was the first to observe that when a drop of mercury was placed on a grooved surface between the electrodes it moted towards the negative pole; and he also observed that “ a drop of mercury in a horizontal tube, with dilute acid on both sides, moved at the passage of the electric current through the tube towards the negative electrode.” 4 This latter phenomenon was fully investigated by Lippmann,5 and led, along with researches by Quincke, not only to a theoretical explanation of electro-capillary action, but also to the construc- tion of the capillary electrometer. It is now known that these phenomena, both as seen in the experiment with the globule of 1 Read before the Philosophical Society of Glasgow, January 17, 1883. 2 For an historical account of this subject see Lippmann, Annales de CTiimie et dc Physique, 1875, p. 540. Also references in arts. “Capillary Action, by Professor Clerk Maxwell, Encyclop. Britann., vol. v. p. 65 ; and “Electrolysis,” by Mr. W. N. Shaw, vol. viii. p. 108. See also art. “Electricity,” Watt’s Diet, of Chem., third suppl., vol. viii. part i. p. 714. 3 Gilbert’s Annalen, t. xxxii. p. 261, 1809. 4 Art. “ Electrolysis,” op. cit. 5 Lippmann, Comptes Rendus, 1873, p. 1407 ; Annales de Chimieet de Physique, 1875, p. 494; Poggendorffs Annalen, cxlix. p. 547; also translated in Phil. Mag. [4], xlvii. p. 281.