Take a block of wood at least 3 in. square and with an extension bit [Such a bit may be had of Amateur Work for a reasonable price], bore a hole E2 in. diam eter 1 in. deep, with the same center, continue this hole F 1 in. diameter another inch, and with a bit large enough to hold the tube used in the common pump finish this hole through. In this hole the tube C is to be fastened. At the upper end of H a small leather valve V is fastened by means of a tack. In one side of the block bore another hole A 1 in. diameter and 1 in. deep. Continue this with a 3/8 in. bit through to F and make another valve that will drop and cover the hole, as in the figure. Make a 3/8 in. plug to fit this hole and fit into this a tube, D. After making these holes it would be well to paint our block inside and out with melted paraffine. One inverted chimney will fit in the hole, E, and may be fastened in with putty. The others should fit very tight and can be stuck in with shellac. If these joints are waxed with paraffine they will be waterproof.
A piston, P, similar to the one used in the tube but of solid wood, should be made and fastened to a rod B. Our pump is now ready for work. As made it may not not pump air, but should pump water. Invert the pump, pour water through C until E and F are filled with water and water runs out through D. Hold the fingers over the end D and set the pump upright in a vessel of water. Push down the piston P and the pressure of water in E will close valve V and send out a stream through D. Raise the piston P and the pressure of air outward will press against A, shutting valve there, but will force the water up through C and valve B. Upon each downward stroke of P water will be forced out at D, and on each upward stroke water will be pressed up through V and fill the space E and F.
If a continuous flow should be wanted the tube D should be replaced by a bent tube, such as S, which ' should pass through a stopper into an inverted bottle. O. Another tube, bent as T, should pass through the same stopper. Holes may be made in a cork stopper by means of a rat-tail file, and bent tubes maybe obtained at a druggist's, if no other dealer in town keeps them. With such an air chamber a continuous flow of water from the tube, T, may be obtained. The working of the valves is the same as above, but as the water passes from S into the chamber, O, and covers the opening of T the air in O is compressed and exerts a continuous pressure on the surface of the water in O. When the water is entering O through S the pressure is forcing it out through T; and when not entering, i. e., the up stroke of P, the valve A prevents any water from being forced back through 8, and the compressed air continues to keep the water running in a steady stream through T.
In some cases two pumps are connected with the same air chamber, and the piston of one is rising while the other falls, so that in any case there may be had a stream flowing uniformly from the hose or pump spout.