|| Packard's apparatus is used to investigate
the spatial relationships of a body in vertical motion in a constant gravitational
It was invented by John C. Packard of Brookline High School in Brookline, Massachusetts, and was patented on December 17, 1907. The original manufacturer was the L.E. Knott Apparatus Company of Boston, which sold it for $6.25 in 1916.
The inclined plane is leveled from side to side using the spirit level at the top. A piece of graph paper is placed on the sheet of plate glass forming the top of the apparatus, and over this is laid a sheet of carbon paper, face down.