Gas electrode for general use / by G.S. Walpole.

  • Walpole, George Stanley.
Date:
[1913]
Catalogue details

Licence: In copyright

Credit: Gas electrode for general use / by G.S. Walpole. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    apparatus has been used for all cases. When dealing with a solution containing carbon dioxide or other dissolved gases a slight modification of technique is all that is necessary. Apparatus. The modifications of existing apparatus which I have employed consist of (1) the electrode vessel, (2) the filling apparatus, (3) the support in the constant temperature bath. The electrode vessel (ABD, Fig. 1) is somewhat more complicated than the simple V shape generally employed, but this is amply compensated for by the simplicity of the other parts of the apparatus and the many conveniences accompanying its use. I have used throughout the platinum point advocated by Micfiaelis, just making contact with the surface of the fluid. The platinum point is mounted at the end of a glass tube A. The protruding end is blackened in the usual manner. The other end makes contact with a small globule of mercury placed inside the tube. The lower end of A may be ground to fit the outer tube B or else a joint may be made by means of a rubber stopper as in the diagram. Attached to B at the side is a very fine bore capillary tube carrying a tap i), and at the lower end is a second capillary tube not quite so fine, of about 1 mm. bore. At the lower end of this may be fitted a very small glass stopper, but it is not necessary and has certain disadvantages. The filling apparatus used with all these electrode vessels is depicted together with other apparatus in Fig. 2. It consists of a three-way piece F connecting a 5 cc. all-glass syringe G, well lubricated with vaseline, a short piece of fine-bore stout rubber tubing H and a glass tube carrying a glass stopcock which is connected with the hydrogen supply. As support for the electrode vessels in the constant temperature bath, while taking potentiometer readings, I have used a glass trough K (Fig. 1) in which the electrode vessels stand side by side in a suitable connecting solution. For single electrode vessels a large test tube serves excellently. The other half-electrode employed, a tube from which leads into the glass trough, is also immersed in the water-bath. I have used principally the calomel-saturated potassium chloride half- electrode recently described by Michaelis and Davidhoff [1912] and a standard calomel N/10 KC1 half-electrode. The connecting solutions were saturated potassium chloride solution, saturated ammonium nitrate [Cumming, 1907],