New Telescope.

Professor Pickering, director of the Observatory, has lately devised an atteachment to a photographic telescope of such a nature that eight plates, eight by ten inches each, can be exposed in succession without disturbing the telescope. The telescope is regulated by clock-work and is designed to photograph all the bright stars that cross the meridian during the night. This instrument is much more powerful than the one of similar construction which has been in use at the Observatory during the last few years.

For astronomical work every photographic plate must be tested for sensitiveness. Mr. Ring, assistant at the Observatory, has found the shape which an aperture must have in order to give a shaded area on each plate that will vary in intensity in arithmetical ratio. By means of a narrow strip on each plate, varying from a very light shade to one of considerable darkness, the magnitude of the stars photographed may be measured with accuracy.