Many years ago I discovered Circa Lighting while researching 1700's Smoke Bell Lamps, also known as Hundi lamps, which I still love and carry in my shop today.
Recently, I rediscovered the Atlanta-based lighting shop. They've posted a great explanation for French wiring vs. standard wiring in lamps. Some of you may recognize this as a technique I've used on a few of my custom-created lamps.
Here are the basics differences between the two types of wiring:
Most table lamps are constructed with the electrical cord extending down from the bottom of the socket through the center of the lamp and exiting out the bottom or side of the base. The cord is then
completely hidden inside the body of the lamp. This is called standard wiring.
French wiring simply means the electrical cord exits through the bottom of the socket rather than through the lamp base. Especially appropriate for solid crystal items such as the lamp pictured above, this type of wiring also works for converting antique oil lamps to electric while maintaining the integrity of the glass font.
These great images, courtesy of Circa Lighting, demonstrate the idea nicely: