Make a three-armed siphon as shown in Fig. 77. Put two arms in tumblers filled writh water, suck air out of the third arm until the water runs, and then put it in an empty tumbler.

Stand the three tumblers on the table. Does the water run until the levels are the same?

Put one tumbler on a book. Does the water run into the other two tumblers until the levels are the same?

Return the one tumbler to the table and put the other two on the book. Does the water run from both tumblers to the lower tumbler until the levels are again the same?