8. Mode of finding the annual parallax by double stars 9. Cassiopeia, with the position of the new star of 1572 34. Representation of a treble system. 36. Position of the small stars composing & Lyræ 39. Explanatory of the position of the sun in the Milky Way 156 40. Telescopic view of the stars in Præsepe 41. Telescopic view of stars in Orion's Sword. 46.* Principal stars in Lyra, showing the position of an an- 47. Nebula in the shape of a dumb-beli 59. Represents an extensive diffusive nebulosity 60-62. Various kinds of nebulosities joined to nebulæ 72. Nebula in Orion, as seen in 1740 73. Ditto, as seen by Sir W. Herschel in 1811 76. Representation of a meteoric shower 77. Orbit of the body whence the November meteors are 78, 79. Two views of the comet of 1807, by Schroeter and 83. Portion of the orbit of the comet of 1680 84. Orbit of the comet of 1832, with the relative position of ib. ERRATA. Page 71, line 15 from top, for "tenacity" read "tenuity," THE SIDEREAL HEAVENS. INTRODUCTION. In a work lately published under the title of "CELESTIAL SCENERY,"* I endeavoured to exhibit a pretty full display of all the prominent facts connected with the motions, distances, magnitudes, and other phenomena of the planets, both primary and secondary, and of the observations and reasonings by which they are supported. These bodies, forming a part of the solar system to which we belong, and lying within the limits of measurable distance, can be more distinctly surveyed, and their magnitudes and other phenomena more accurately investigated, than those of the remoter orbs of the firmament. Hence, in consequence of the accurate observations of modern times, we can now speak with a degree of certainty and precision respecting their order and arrangement, their periodical revolutions, their distances from the sphere we occupy and from the centre of the system, their real bulk, the appearance of their surfaces, and the objects which diversify their respective firmaments. But when we pass the boundary of the planetary system, and attempt to explore the orbs which lie beyond it, we have to travel, as it were, through dark and pathless regions; we have to traverse an immense interval, which has hitherto baffled all the efforts of human science and ingenuity to determine its extent. The fixed stars lie completely beyond the dominions of the sun; they feel not his attractive influence; they revolve not around him as a centre, nor are they enlightened by his effulgence. It follows that our knowledge of those remote luminaries must be extremely No. 83 of Harpers' Family Library. imperfect, and our views of the distant regions in which they are placed comparatively limited and obscure. But notwithstanding the immeasurable distance of the starry regions, and the limited nature of human vision, we are not altogether ignorant of those remote and unexplored dominions of Omnipotence, or of the magnitude and splendour of the bodies they contain. The telescope has enabled us to penetrate the vast spaces of the universe, and has opened a vista through which thousands of suns and systems are distinctly beheld, which would otherwise have been for ever veiled from the view of mortals. It has extended the boundaries of our vision thousands of times beyond its natural limits, and collected the scattered rays of light from numerous distant orbs, which, without its assistance, would never have entered our eyes. It has served the purpose of a celestial vehicle to carry us towards the heavens, and has produced the same effect on our visual powers as if we had been actually transported thousands of millions of miles nearer the unexplored territories of creation. Guided by this noble instrument, scenes and objects have been disclosed to view of which former generations could form no conception, and which lead the reflecting mind to the most elevated views of the perfections of the Deity, and to the most expansive prospects of the grandeur and magnificence of his empire. For a considerable period after the true system of the world was recognised, astronomers were disposed to consider the stars as so many insulated luminaries, scattered almost at random throughout the vast spaces of the universe. Having engaged in no very extensive surveys of the celestial vault, and resting contented with the idea that the stars were so many suns, dispersed in a kind of magnificent confusion throughout the immensity of space, they seemed to have formed no conception of any specific difference in the nature of these bodies, or of any systematic arrangement as existing among them. Hence it happened that no discoveries of importance were made in the region of the stars, from the time of Huygens and Cassini till near the latter part of the eighteenth century; so that a whole century elapsed without materially enlarging our views of the sidereal heavens, and of the variety, order, and arrangement of the numerous bodies which every portion of those expansive regions presents to view. During the last sixty or seventy years, the attention of astronomers has been |