Wash Bottle: a Laboratory Wash Bottle with a Slit Valve (Boy Mechanic, 1915)

Fit a stopper to a large-mouthed bottle and bore three holes through it for the tubes.

Use brass or glass tubes. Bend the nozzle tube E so it reaches the bottom and points out over the side (sketch); the air tube A and relief tube D only pass through the stopper.

On the lower end of air tube A fit a thick piece of rubber tubing B, stoppered at its bottom end, and cut a slit C in its side: blown air opens it, and it closes again to hold the pressure. Push the three tubes through the stopper and fit it in the bottle. To use: fill with water, blow into A, then close D with your thumb; water jets steadily from E and stops the moment the thumb lifts.