Saturday, March 28, 2015

South Facing Dragon

This is a model of a 2,000 year old military weapon. The Chinese invented the differential gear so their "dragon" always faced in the same direction no matter how the cart was twisted and turned. The military advantage was that in the heat, confusion, and dust of battle the generals could always tell what direction they wanted to advance. 


  1. That is fascinating. Great photo.

  2. Replies
    1. Most all cars and trucks have a differential gear allowing the rear wheels to turn a different speeds around corners, but the Chinese applied this gearing to keep a figure or dragon pointing in only one direction as the cart turned. It is a non-magnetic compass. Yes, genius!