Honoring X geometry

I'm running KDE 2.2.2 and I can't figure out how to get KDE to honor an X geometry specification. My .Xdefaults file contains the line xclock*geometry: 208x29-0-46 but xclock still shows up in the upper lefthand corner with a different-size window than I asked for. I'm starting xclock from my KDE autostart folder. Paul Abrahams