The device in the right is in the Millington/Barnard Collection at the University Museum at the University of Mississippi.
The wooden ball rolls down the groove in the semi-circular
ramp at the right, and then is projected out into free fall. It follows
a parabolic path, traveling equal distances in successive units of time
in the horizontal direction and quadratically increasing distances in the
vertical direction. The larger numbers on the board give the total vertical
distance and the smaller numbers give the distances during each successive