Its not perfect though. There's a knob for tightening near the pivot on the wall, and that knob needs to be tightened very hard for the lamp not to droop downwards. Its with a wooden screw thread, of course. I think a metal screw, though not as nice looking, would have worked better for applying a large clamping force without turning the knob so hard.
My friend Ron Walters has also made some scissors extending lamps -- less ornate but more engineered.
And another lamp. This one is much simpler but easier to adjust.
But it doesn't look as pretty as the other lamp.