I used to wonder what "jeweled movement" meant. Thinking of watches as luxury items, I associated "jewel" with this aspect and I had no clue that there was such thing as jeweled bearings.
I read about John Harrison and how the Longitude Problem lead him to create the first accurate timepiece that would remain accurate through variation in temperature, humidity, pressure, and movement of the timepiece (as in on a rocking ship). Reducing friction without using lubricants was one key as the lubricants would change viscosity when the temperature changed. Jeweled bearings are the current evolution of this idea, as far as I know, and are particularly suited to small applications such as pocket and wrist watches.
Here's a version of John Harrison's tale and the creation of his masterpieces, H-1, H-2, and H-3:
http://www.antique-pocket-watch.com/...e-problem.html
- GregB