Dr. Hughes, an Australian physicist has taken exception to the Oxford Dictionary’s definition of a siphon, http://www.telegraph.co.uk/news/worldnews/australiaandthepacific/australia/7709513/Physicist-spots-99-year-old-mistake-in-Oxford-English-Dictionary.html" [Broken] claiming that a siphon works by gravity rather than by atmospheric pressure. Many people still disagree with this view. I thought that if there was any one forum where the matter could be probably be decided one way or the other, it was probably Physics Forums. And to help decide this issue there is no better place to start than with the broken siphon. Given below is a diagram of a broken siphon. At the beginning of the experiment container B is four fifths full of water and container A is filled with a little bit of water which is retained by closing pipe d. Pipe c extends from the bottom of container B to near the top of container A, pipe d leads from the bottom of container A to the atmosphere. When pipe d is opened, water begins to flow from pipe d to the atmosphere, and water flows from container B into container A through pipe c. This continues for a short time after which the flow of water stops. So how does a siphon work ?