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A crystallographic analysis of a characteristic shape of particle found in zinc oxide produced by burning zinc vapor has been made with the aid of the electron microscope. This particle consists of four needle-shaped crystals united at a common juncture. The spatial angles among the four crystals were determined from stereoscopic micrographs with the use of the stereographic projection. The crystals were found to be united by twinning on planes of the form (112).
M. Luther Fuller (Tue,) studied this question.