The Coin in Equilibrium
Here is a curious demonstration of the balancing of bodies having their center of gravity displaced by a counterpoise.
We propose to keep a coin horizontally in equilibrium on the rim of a tumbler, and it must rest on the glass only by its extreme edge, as shown by the figure which gives the complete demonstration.
Take a silver dollar and place it between the prongs of two forks covering each other, then place the edge of the coin upon the glass and draw the handles of the forks together, or distend them till the whole are balanced. The center of gravity will then be at the point of contact, and you may give a slight swing without the risk of breaking the equilibrium thus obtained.