PREFACE. HE favour with which the articles and star-maps, entitled "The Midnight Sky at London," were received by the readers of the Leisure Hour, has encouraged the Committee to re-issue them, with some additional astronomical papers, in a separate and more convenient form. In the arrangement of this work for the press, the author has made a complete revision of every part, omitting many paragraphs which had reference only to the time of the serial publication, and adding much important matter which, in a permanent book, should have a place. He has not only re-written many portions of the text, but he has also inserted some remarks on the Solar System, including the Sun, the Earth, the Moon, Mercury, the Minor Planets, Uranus, Neptune, and Comets, none of which were described in the original papers. Considerable additions have also been made in other parts of the work, especially in the chapter on "General Notes on the Fixed Stars." With regard to the star-maps, the author believes that, with the assistance of the corresponding index-maps, the student will experience but little difficulty in recognising the principal stars and constellations in the heavens. There may be a partial failure at first, but by persevering in a systematic comparison of the diagrams with the sky, any intelligent person will soon conquer whatever difficulty may arise. That many persons have succeeded in recognising the principal objects, by the use of the sky-views, has been proved by the numerous gratifying communications which the author has received from correspondents resident in all parts of Great Britain, during the publication of the articles in the pages of the Leisure Hour. Astronomy has for ages been one of the most popular of the sciences. What greater delight can be experienced by those who take pleasure in the contemplation of natural objects, than by becoming personally acquainted with the relative positions of the planets and principal stars; with the general contour of the different constellations; and with many other illustrations of God's creative wisdom as displayed among the starry hosts above and around us? "Why did not somebody," says Carlyle, "teach me the constellations, too, and make me at home in the starry heavens, which are always overhead, and which I don't half know to this day?” Now, it has been the earnest desire of the author to be the "somebody" of Carlyle, and if his very familiar notes have enlightened the minds of his readers, even if only in a small degree, the numerous views of the sky and the illustrative descriptions will not have been prepared in vain. GREENWICH: October 1, 1869. Greek letters being used to distinguish the principal stars, the following alphabet E. D. INTRODUCTORY AND EXPLANATORY. FEW brief and elementary explanations will enable the reader to understand the method adopted in the construction of the following representations of the starry heavens as seen at midnight. Although all the star-maps of the northern hemisphere are given for London exclusively, yet they are equally available for every place on the surface of the Earth where the latitude is 51° 30′ N. The selection of London is a purely arbitrary one; any other city in the same latitude would have answered our purpose as well. In all districts situated within a few degrees north or south of latitude 51° 30′ N., the star-views are also approximately correct, so that an ordinary observer, without a telescope, would probably fail to detect the difference. It is of no consequence, therefore, in what part of London, or its neighbourhood, the observer is located. It may be in the heart of the City, on the heights of Hampstead and Highgate, among the denizens of Kensington or Belgravia, or in the astronomical atmosphere of Greenwich. At all these places, the appearance of the heavens at midnight is, for all practical purposes, the same. And with slight and unimportant differences, which easily admit of correction, the same remark holds good of the whole of Great Britain. In the sky-views of London, the observer is supposed to be looking north, directly over St. Paul's Cathedral, and looking south over Greenwich Hospital, with the Royal Observatory in the background. In the representations of the southern heavens, different places have been selected on the parallel of 34° S. latitude, including views in the Cape of Good Hope, Australia, and South America. In one or two instances, the position of the stars is as seen at sea from on board ship. With respect to places in the same parallel of latitude, but separated by a considerable difference of longitude, there is one important circumstance which the reader must bear in mind. As all the diagrams of the sky of the northern hemisphere represent the view of the heavens at the local midnight of London, and those of the southern hemisphere the local midnight at the respective localities, so, if we wish to |