The Reason Why / A Careful Collection of Many Hundreds of Reasons for Things Which, Though Generally Believed, Are Imperfectly Understood

by Robert Kemp Philp

Fig. 40.—AIR PISTOL, OR "POP-GUN."

855. Why must the handle be drawn out, before the cork is placed in?

Because otherwise a partial vacuum would be formed between A and C, and there would not be sufficient air to force out the cork by the return of the piston C D.

856. Why does water rise in a syringe when the handle is drawn out?

Because the pressure of the air on the water outside of the syringe, forces it into the space vacated by the drawing up of the handle, and where, otherwise, a vacuum would be formed.

Fig. 41.—SYRINGE, WITH JET OF WATER.

857. Why does not the water run out when the syringe is raised?

Because the pressure of the air upon the small orifice resists the weight of the water.