Immersion coating, definition

The antimony electrode is an example of electrode of the type metal-oxide. It consists of a rod of metallic antimony, coated with a natural film of antimony trioxide and immersed into a solution with a definite hydroxyl ion concentration. Its function can be explained as follows antimony emits at first ions into the solution... 

In the second case, the precipitate which degrades the transparency of the liquid remains initially in suspension throughout the mass, but floats up then with an extreme slowness, and, after a few days, forms a definitely separate layer in the upper part of the liquid one then collects the limpid portion by means of a siphon which starts by a side tube, and the preparation is finished. I must point out that when one introduces into the liquid the short branch of the siphon, a portion of the precipitate forms around the external surface of the tube a kind of reversed cone it is thus necessary, before starting the siphoning, to remove this coating. For that, one initially leaves the whole at rest for a quarter hour, then one agitates a little from side to side the immersed branch of the siphon the cone of precipitate is detached as small blobs which float up little by little and will join the upper layer. The liquid collected under these conditions is much better than the preceding one can employ it in experiments at once after the operation of the siphon the test bubbles which it provides have a maximum three hours of persistence finally it is preserved sufficiently well for about a year. 

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