Laboratory Notes by Professor Tait c. Capillary Phenomena at the Surface of Separation of two Liquids

Extract

The only difficulty in this investigation is the selection of two liquids, neither of which will line the interior of the capillary tube so as to disturb the behaviour of the other. This was effected in various ways, most simply by employing water and sulphuric ether; for when these liquids are shaken together and allowed to come to rest, the result is the production of a very sharply defined bounding surface between a weak solution of water in ether (above) and a weak solution of ether in water (below). The observations and measurements were made with contiguous portions of the same capillary tube,–one dipping into the upper, the other into the lower, layer.