The Siphon Bird Waterer: An Oblique Cut That Lets the Air In

"My invention relates to drinking and feeding appliances designed for bird-cages and made on the principle of a common siphon barometer". In earlier drinkers the small tube was "cut square—that is to say, at right angles to the axis of the tube—which has the disadvantage that by the action of the vacuum formed in the upper part of the vessel on the one hand and the outer air-pressure on the other hand the water is kept in equilibrium, so that the feeding-basin may be emptied without water being allowed to flow from the reservoir." "For the purpose of insuring the outflow from the reservoir to the feeding-basin b in proportion to the removal of water from the latter by the bird the bottom end of the aforesaid small tube is cut obliquely for facilitating the entrance of air-bubbles."

Cut two 20 cm lengths of clear acrylic tube. Close the bottom of each with a rubber stopper. With a hacksaw and knife, cut a window 2 cm high in the side of each tube, just above the bottom stopper: this is the basin. Drill a hole through a second stopper for each tube and push a 3 cm length of vinyl tubing through it. Cut the lower end of one tubing square and the other at about 45°. Push each stopper up the tube until it sits just above the window, tubing pointing down into the basin: this is the partition. Stand the tubes upright, fill each reservoir from the top and close it with a third stopper. Draw 1 mL at a time from each basin with the pipette, and note after each draw whether bubbles rise and the basin refills.

**Hermann Quittner** of Berlin filed US 811,870 on 20 December 1904; it was patented 6 February 1906. He hung the tube in the cage by a hook at its top, and noted the same appliance could hold seed, which settles to its own slope in the basin. **Honest limits.** The notebook gives the holding height of a round opening only; an oblique cut exposes its upper edge first, so air gets in sooner, but the notebook does not model that shape. Tube sizes are examples. Your two drinkers are the measurement.