This topic is somewhat arcane, and yet we shall give it quite a lot of attention. The reason is not because siphons are necessarily any great design product to be sought after. The reason is because siphons are potentially quite dangerous and destructive, if they occur unexpectedly and are not properly controlled. (As used in this context, a siphon is a flow condition, not a particular piece of hardware.) Siphons are formed by some type of sealing action at the two ends of an open liquid circuit, as a combined consequence of the pipe geometry and flowing condition, and they...