From the 1916 catalogue of the L.E. Knott Apparatus Company of Boston: "VON NORDROFF COLOR APPARATUS. This apparatus was designed by Dr. Von Nordroff, Principal of the Stuyvesant High School, New York City, for the convenient and satisfactory study of color phenomena where only one Projection Lantern is available. Our method of mounting is such that it is equally well adapted for use with the Port Lumiere. 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." The price was $32.00.

   The two examples below are in the Jack Judson Collection at the Magic Lantern Museum in San Antonio, Texas. The apparatus on the left is unmarked, but is clearly the one made by Knott. In the 1916 catalogue it is shown mounted on a short stand similar to the apparatus on the right, which is listed at $36.00 in the 1936 Central Scientific Catalogue. The apparatus is accompanied by a series of color filters to study primaries and secondaries, and other color phenomena.

This example of Von Nardroff's apparatus was made by Central Scientific Company of Chicago about 1960. I bought it for the Greenslade Collection to try it out as a piece of demonstration apparatus.          Unfortunately, it was missing its color filters. A visit to the Bolton Theater on the Kenyon campus turned up a spare set of samples of colored gels used in spotlights, and from these I was able to find examples of primary colors (red, blue, green) and false, or subtractive, primary colors (magenta, cyan and yellow). When light from either of these two sets was combined, a white region was observed where the circles of light overlapped.    A modern slide projector was used as a light source, and the three beams were made to converge by adjusting the three lenses in and out.

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