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Such arrangements are called gravity cells; but the separation is never perfect, the heavy liquid slowly diffusing upwards.57 Daniell Gravity Cell.—In this cell, shown in fig.

The gravity cell has until recently been extensively used in telegraphy, and continues in use in short-distance telegraphy and in automatic block signals.

My Dear Young Man: You will need several batteries when you come to set up your radio receiver but you won’t use such clumsy affairs as the gravity cell which I described in my last letter.

This apparatus is good to work a gravity cell when it needs regulating.

The gravity cell is really a two-fluid cell in which the two liquids are kept separate by the joint action of the current and the force of gravity.