72.0 kPa at the top, and the atmosphere is doing the holding

The absolute pressure along a siphon, from the source surface at the left, over the crown in the middle, to the outlet at the right, with the tube's height drawn beside it. The pressure falls as the liquid rises and recovers as it descends: the minimum is at the top and is 72.0 kPa against an ambient 101.3. Nothing here *pushes* the liquid along — the profile is symmetric about the crown, and a push would have to be one-sided. What the atmosphere does is keep the whole column above the vapour pressure, which is a different job with a different limit.

5 essays call siphon-profile. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the one its essay argues about.

It is also the blast radius. Changing siphon-profile changes every figure listed here at once, and on this site it may change what they assert as well as what they show — which is what has to be rebuilt and looked at before the change is believed.