ABSTRACT
Lewis Swift, a well-known comet discoverer, devoted a considerable time to the successful search for new nebule; and G. Bigourdan, of the Paris Observatory, has performed a very troublesome task in determining accurately the positions of hundreds of these objects. When Draper photographed the Orion nebula, many reflecting telescopes, whose special advantages for the recording of faint nebulosity render them much more suitable for the purpose than refractors, have been employed in similar work. In 1883 Dr A. A. Common of Ealing obtained with his large reflector a very fine photograph of the Orion Nebula, for which he received the gold medal of the Royal Astronomical Society. Max Wolf, at Heidelberg, and Barnard and W. H. Pickering, in America, worked in the same field, the former publishing in 1902 a catalogue of about 1500 nebule north of the Milky Way. In fact almost every kind of nebula seems to hint at some stage of the same development.
