Friction, Lubrication and the Lubricants in Horology

by W. T. Lewis

Fig. 7.

Fig. 8.

1. Thrust vertically into water three glass tubes, A, B and C (Fig. 8), open at both ends. You notice the water ascends in each to a different height, and that the ascension varies inversely as the diameter of the bore; i. e., the smaller the bore, the higher the water ascends.

2. Seal one of the tubes at its upper end. The water enters but little, as shown at D (Fig. 8), on account of the resistance of the air pressure within the tube.

3. Thrust vertically two plates of glass into water, and gradually bring the surfaces near to each other. Soon the water rises between the plates, and rises higher as the plates are brought nearer. If their surfaces be mutually parallel and vertical, the water rises to the same height at all points between the plates, as shown at A (Fig. 9.)

Fig. 9.

4. If the plates be united by a hinge, and form an angle, the height to which the water ascends increases as the distance between the plates decreases up to their line of junction, where it attains a maximum, as shown at B (Fig. 9.)

5. Decrease the angle between the plates, and the water ascends higher, as shown at C (Fig. 9.) Thus it is seen that the ascension varies inversely with the angle between the plates; i. e., the smaller the angle, the higher the water ascends.