BALLS are supported aloft in the following manner. Underneath a cauldron
(fig. 45), containing water and closed at the top, a
fire is lighted. From the covering a tube runs upwards, at the extremity
of which, and communicatmg with it, is a hollow hemisphere. If we put a
light ball into the hemisphere, it will be found that the steam from the
cauldron, rising through the tube, lifts the ball so that it is
suspended.