The Sun:

IT is a commonplace to refer to the sun as the nearest star, unique in presenting a disk for detailed study and thus deserving the closest of observation. In this book, Dr. Abetti, the director of the Arcetri Solar Observatory at Florence, surveys our knowledge of solar phenomena gained from the rather restricted direct telescopic observations to those embraced by the extensive field of spectroscopy. How rich the results have been may be quickly appreciated by looking through the numerous illustrations. Behind some of these lie years of devoted research and great inventive ability, as in the case of a spectroheliogram of beautiful definition, the detection and measurement of the magnetic field of a sunspot, or the recording of the sun's inner corona without a total eclipse.The Sun:its Phenomena and Physical Features. By Giorgio Abetti. Translated by Alexandra Zimmermann and Frans Borghouts. Pp. 360. (London: Crosby Lockwood and Son, Ltd., 1938.) 20s. net.