Water thief

The term "water thief" refers to three devices – one ancient and two modern.

A water thief is a synthetic rubber fitting that attaches to an unthreaded faucet (American English) / tap (British English) on one end and a common garden hose on the other. It is commonly used to fill fresh water tanks in recreational vehicles when a threaded hose bib is not available.
A water thief allows firefighters to break down one larger line into several smaller ones, each with independent control of water flow at the valve.^[1]
Another device, used in antiquity, was called a "water thief" or "clepsydra". Carl Sagan described it in his book Cosmos as "a brazen sphere with an open neck and small holes in the bottom, it is filled by immersing it in water. If you pull it out with the neck uncovered, the water pours out of the holes, making a small shower. But if you pull it out properly, with the neck covered, the water is retained in the sphere until you lift your thumb."^[2]^[3]^[4]

References

^ "Stealing" Water with the Water Thief by Doug Leihbacher
^ Carl Sagan (1980), Cosmos, Random House, pp. 179–80.
^ The earliest description of the device is in: Empedocles, Fragment B100.
^ Robert Boyle, A Continuation of New Experiments Physico-mechanical, Touching the Spring and Weight of the Air, and Their Effects, Henry Hall, 1669, p. 29 (Boyle's explanation of the ascension of water in sucking pumps) and The Works of the Honourable Robert Boyle: In Six Volumes, Vol. I, J. and F. Rivington, 1772, pp. 191–2: "if a gardener's watering-pot be filled with water, the hole at the top being stopped, the water will not flow out of any of the holes in the bottom; but if the finger be removed to let in the air above, it will run out at them all..." See also Marcus Hellyer (ed.), The Scientific Revolution: The Essential Readings, Blackwell, 2008, p. 77 (a commentary on Boyle's observations about gardener's watering-pot) and Boyle's law.