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Rh however, a most extraordinary effect, and on this account is to be recommended.

A piece of paper is placed at the bottom of a glass tube or chimney used for gas, which is then filled with water, while the top of the tube is covered with a second piece of paper. The right hand is then placed on the top paper and the position of the tube reversed. The papers are then, each in turn, removed, but the water does not fall from the cylinder; on the contrary, it remains suspended without visible means of support. The papers are now replaced, and the top one is pierced with a hatpin, when, on the pin being withdrawn, the water at once falls into a basin placed ready to receive it under the tube.

This surprising result is due entirely to a well-known natural law, viz., the pressure of the atmosphere, and is nothing more nor less than a modification of the old schoolboy trick of keeping a glass of water inverted by means of a sheet of paper. The new arrangement will, however, require special explanation.

Each end of the cylinder is fitted with a glass cap, grooved to fit into and over it at the same time; this is necessary to avoid slipping. The ends of the tube, also the edges of the caps, must be ground, so that the point of juncture shall be