Proof of Moon's Rotation

Nikola Tesla Shows Conclusively That Speculations as to Orb's Movement Aro Wrong.

Nikola Tesla communicates to the Electric Experimenter a striking proof of the fact that the moon does not rotate on Its axis, but only seems to do so. Much of his article is extremely technical, involving the complex mathematical formula of kinetics, but the following extract, with the accompanying diagram, can be understood by anyone.

The diagram shows a system composed of eight balls (M), which are carried on spokes (S), radiating from a hub (H) rotatable around a central axis (O) in bearings supposed to be frictionless. The balls are not a part of the spokes, but are supported in pivots (s) which are nominally loose, but can be tightened as to permit free turning or rigid fixing as desired. To facilitate observation, the spokes are provided with radial marks and the lower halves of the balls are shaded.

Now, with the pivots loose, start the apparatus going in the clockwise direction marked by the black arrow — from position 1 to 8 and by the time it has made the whole circuit of (O) it has shown its whole circumference to any observer at (O). Thus it has revolved on its axis.

Now tighten the screws so that the ball no longer turns freely on its axis, but becomes a solid part of the spoke. The side that is turned toward (O) at the beginning remains always turned Toward (O), and an observer at (O) sees only one face of the ball in its revolution.

Now, the latter is exactly the case of the moon. If the moon were free to turn upon its axis, we on earth should see its whole circumference in the course of a month and we might know what is on the other side of the moon as well as we know what is on the one face with which we are all familiar.