Myst 3: Exile Walkthrough
Voltaic: The Steam
OK, you've got power and the lava going. Now for the steam. Go back near the airship. Go near the dials. Now look UP. Yes, there are three tiers of these darn things. Close all the ones at the bottom. Use the little elevator to go up. Close them all again. Now go up again. OK, at the top, close one. Go back down. Close just 2, and back down to the bottom. Open up 3.
This should be enough power to get the airship going. If you look at the dial, you want the LONG thing pointing at the red.
The Myst 3: Exile Walkthrough