ACCORDING to an article in The Times of June 22, accommodation for a planetarium is being included in the plans for rebuilding the centre portion of the Science Museum, South Kensington. It is stated that Germany already has thirteen planetaria, America four, Italy two and Holland, Sweden, Austria and the U.S.S.R. one each. Such an instrument enables celestial bodies to be shown as bright objects on the inside of a large darkened dome, and by means of elaborate mechanism their movements can be demonstrated. The method thus marks a great advance on the orrery, in which the positions and movements of bodies in the solar system are represented in a mechanical model. It will be recalled that the first Zeiss planetarium, erected at Munich, was described and illustrated in NATURE of December 27, 1924, p. 937.