A Multiple Projector for the Huggins Masks

The usual procedure for making two-dimensional fourier projections of crystal structures by means of the Huggins masks requires the expenditure of time in the photographic darkroom during which errors may be made. These errors can be corrected only by a repetition of the entire laborious procedure of successive exposures of the plate. An apparatus is described whereby 144 Huggins masks are projected simultaneously on a screen and the result photographed. The projection is accomplished without lenses and the cost of production is thereby reduced considerably. Grooves are provided for changing the signs of the fourier coefficients at will. Rheostats on the projection lamps are provided for controlling the lumination in proportion to the magnitude of the fourier coefficients.