Theoretically speaking, would it be possible to manufacture a wristwatch with a nitorgen-purged interior? Obviously something like this would be a superfluous feature for most people, but it would all but eliminate the possibility of the crystal fogging up, as there wouldn't be any water vapor whatsoever inside the watch. Aside from the obvious difficulties of having to construct a watch in an oxygen-free environment, the other major problem I see would be the crown--even with a screw-down, once you unscrew it and start manipulating it the seal is less than perfect, and regular air can start creeping in, albeit in very tiny amounts. Scientific vacuum chambers deal can deal with this issue using magnetized manipulators, but not only would that be impractical to implement at such a small scale, I don't imagine having a magnet--even a small one--that close to the movement would be good for the watch. Anyone more experienced have suggestions on how this could be done?