The Von Nardroff Color Apparatus and Interference Filters, ca. 1916.
Mounted on a short stand, together with a selection of color filters in a wooden box.

Dr Ernest Robert Von Nardroff (1864-1938), a New York City science teacher, invented this color mixer which projects three beams of colored light on a white surface, for the study of color phenomena.

Brass, mahogany, glass on a KNOTT cast iron stand.

H: 7 1/2 W: 9 1/8 D: 7 in.

1916: L.E. Knott Co., Apparatus Catalogue (Boston 19xx), p. 321. "Briefly, it is an attachment that converts an ordinary Projection Lantern into a triple lantern in which each of the three beams of light is independent as to intensity and direction."

Tom Greenslade, "The Von Nardroff Color Mixing Apparatus," The Physics Teacher 43 (2006): 602.

In the Smithsonian, National Museum of American History, Accession 312090 Additional color filters included.