From the 1929 Cenco catalogue, which shows a slightly more modern version of this fork: "This is a fork of generous dimensions and sturdy construction. Because of these qualities it commends itself for use on the lecture table, where its size and driving power render it, and the experiments performed with it, visible through a large room; and insures proper continuous operation without the troublesome adjustment encountered with earlier forks. ...The prongs are drilled on the ends to receiver ... mirrors, so that with two forks Lissajous' figures may be observed. One fork is provided with a stylus [held under the screw on the further tine], and the other has a knurled screw for attaching a cord, as in Melde's experiment. ...$17.50" The mirrors were $3.00 for a pair.