In order to use the floor-push the table must stand in exactly the right place; with the drop-string from a chandelier the cord is continually getting in the way; and as for the portable push that comes from under the table, one must be forever hunting for the button every time the table is set. And yet it is quite possible to avoid all these troubles and construct an apparatus that is always in order and always available, wherever the table may be placed. A visitor at a certain house noticed that the number of the family present at a meal was apt to vary largely, necessitating frequent lengthenings and shortenings of the table. And yet the waitress invariably appeared just at the right time, and whether one end or the other of the table was to be served, she was always on the spot where she was needed. The visitor tried to study it out, but was finally obliged to ask for an explanation of the mystery. The boy of the house smiled and intimated that he was responsible for this domestic miracle; later on, when dinner was over, he removed the centre leaves from the table and displayed the simple apparatus that he had constructed and which had worked for several years without adjustment or repairs. The illustration (Fig. 14) represents the frame of a dining-table with the middle cross-bar made fast to the side-rails, so as to support the mechanism. At both ends, and inside the rail, push-buttons are arranged and wires carried from them to binding-posts close at hand, as may be seen at the left side. The cross-bar at the middle of the table supports a large spool on which the flexible cord is wound, and kept taut by means of a clock-spring. This spool takes up the slack between the ends of the table when it is lengthened or shortened, while the smaller one opposite it keeps taut the feed-wires that come up through the floor. A short distance from the floor the wire is provided with a connector, so that when the rug is removed the feed-wires may be disconnected and slipped down.