135 
on to rise about six feet. The reel was then pushed forward 
until it touched the jet and then let go; it immediately 
began to turn about its axis, but left the jet swinging back- 
wards and forwards, touching the jet each time, and each 
time gaining in speed of rotation. This went on for several 
oscillations, but as it got to turn faster it appeared to stick 
to the jet for an instant before letting go, and having done 
this once or twice, it stuck to the jet altogether and 
remained in contact with it, spinning rapidly. The experi- 
ment was then repeated with the jet at different distances 
and with the larger wheel : the result was the same in 
all cases. I found it possible however either to increase or 
to diminish the force of the jet enough to prevent the reel 
from remaining in contact with it. The limits were about 
2 and 8 feet. 
In experiment No. 8, the position of the reel when free 
was carefully marked, so that the least alteration could be 
noticed, and the jet was placed directly under its centre. 
In this position the jet did not cause the reel to move to 
either side in particular, but to oscillate backwards and for- 
wards. The jet was then pushed slowly forwards, and the 
motion of the ball watched. At first it moved away from 
the jet slightly, and remained away until it was struck 
about 60° from its lowest point, after which it gradually 
came back to its initial position, which it reached when 
struck about 65° from its lowest point. 
The forward motion of the jet being continued, the ball 
began to follow the jet ; the point in which it was struck 
moving upwards very slowly. When the reel finally fell 
from the jet and came back into its initial position, the jet 
missed it by about 2J inches. 
This clearly shows that the position of equilibrium is 
about 25° from the middle of the ball, and for any deviation 
below this point the equilibrium is much more nearly 
neutral than for any deviation above it. 
