316 Proceedings of Indiana Academy of Science. 
atom is dead. The motion of the atom must be imagined. It is usual 
to imagine the needles to rotate about the center with a constant angular 
velocity. This is contrary to the laws of planetary motion as illustrated 
in the Solar system. 
While working with this experiment the thought came to me to rotate 
the mercury and thus rotate the balls. A wooden tray was made with 
an electrode at the center and four electrodes, one at each corner which 
are connected in multiple. By sending a current in at the center elec- 
trode and out at the corners one has an approximately radial current 
flowing at right angles to the magnetic field of the magnet which plays 
the part of the positive nucleus in the experiment. This causes the 
mercury to rotate and carry the balls with it. The apparatus consists 
of a wooden tray as shown in Fig. 3. The dimensions are 15x15 em. 
Fig. 4. Fig. 3. 
and 2 em. in depth. The electrodes C and M are made of platinum. 
It has been found later that the electrodes C can be made of iron without 
appreciably distorting the magnetic field. A and B are binding posts 
which are connected to the electrodes by wires, shown by dotted lines, 
which are in grooves on the under side of the box. The apparatus can 
be centered up by placing one ball on the mercury surface after the 
current has been turned on through both the magnet and the tray and 
then shifting the tray until the ball remains practically still at the center 
of the rotating mercury. 
When two balls are placed on the rotating surface they do not rotate 
about the center on the same circle as one would expect from the Mayer 
experiment. No. 1 first rotates about No. 2, and then No. 2 rotates about 
No. 1, their paths resembling rotating elipses. Figs. 5d, 5e, and 5f are 
