| A standard problem for mechanics students involves
the calculation of the minimum time needed for a body to pass, under the
gravitational force, from an upper level to a point on a lower level. This
is usually called the Brachistrochone problem. The path giving the minimum
time is a segment of a cycloid (known to all children who have played with
a Spirograph drawing toy). The other paths are parabolic and straight.
This apparatus was at the Lawrenceville School in Lawrenceville, New Jersey. I photographed it about 1980 when I spent a week as an exchange teacher at the school. It was given to the school by C. R. Crane for R. T. Crane III, class of 1900.
The 1888 Queen catalogue lists a similar device at $18.00.
This rapidity-of-descent apparatus is at Westminster College in western Pennyslvania.
It is 78 cm in length, 59 cm long and is unmarked.