This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Every fisherman knows that live bait will soon die if they do not receive sufficient air. I have succeeded in keeping bait alive and healthy by using a pail of my own construction, which is provided with a compressed-air space to force air to the surface of the water. The air space A takes up one-fifth of the interior at the bottom of the pail, and an ordinary hand bicycle pump is used to fill it through a bicycle-tire valve, B. The pipe C from the air space extends up along the side of the pail and the upper end is bent so that it just touches the surface of the water. The pipe contains a valve to regulate the flow of air.
After the pail has been standing for an hour or more, the bait will rise to the top. The valve is then opened for a few minutes, and the minnows will soon swim around in the water as when this was fresh. - Contributed by T. Whelan, Paterson, N. J.