With respect to handbooks much depends upon the direction of the observer’s labours, for he will obviously require works dealing expressly with his special subject. As a reliable companion to the telescope, Webb’s ‘Celestial Objects for Common Telescopes’ (4th edit., 1881) is indispensable; as a work of reference, and one forming an exhaustive conspectus of astronomical facts, Chambers’s ‘Descriptive Astronomy’ (4th edit., in 3 vols., 1889) may be recommended. Ledger’s ‘The Sun, its planets and their satellites’ is another good descriptive work. The beginner will find Noble’s ‘Hours with a 3-inch Telescope’ full of very instructive and agreeable material; while the more experienced astronomer, requiring a masterly exposition of the principles of the science, must procure Sir J. Herschel’s ‘Outlines’ (11th edit., 1871). In departmental work books of more exclusive character will be necessary. Thus, students of solar physics will want Young’s volume on ‘The Sun;’ observers of our satellite will need Neison’s ‘Moon.’ Those who find double stars interesting should get Crossley, Gledhill, & Wilson’s ‘Handbook’ and Chambers’s revised edition of Admiral Smyth’s ‘Cycle;’ others working on variable stars will need the Catalogues of Chandler and Gore. Jovian phenomena are well represented in Stanley Williams’s ‘Zenographic Fragments.’ Comets have been fully treated of in works by Cooper, Hind, and Guillemin; while to the observer of eclipses Johnson’s ‘Eclipses Past and Future’ is a valuable guide. Everyone interested in nebulæ will of course require Herschel-Dreyer’s ‘General Catalogue,’ containing 7840 objects and published by the Royal Astronomical Society in 1888. As to planetary observations, the several works of Webb, Chambers (vol. i.), and Ledger, first cited, supply a large amount of detail, almost obviating the necessity for further books. _Past and Future._—Observers and telescopes go on increasing day by day, and the future of astronomy has a most brilliant outlook. Photography has latterly effected a partial revolution in observation, though it can never entirely supersede old methods. Spectrum analysis, too, has formed a valuable acquisition during the last quarter of a century. With the new and refined processes, and with the gigantic instruments which have been erected, we may confidently anticipate many additions to our knowledge, especially in regard to very small and faint bodies which the inferior appliances of previous years have failed to grasp. And it is certain that some of the presumed discoveries of past times must be expunged, because not verified by the more perfect and powerful researches of a later date. Let us place in parallel columns (1) a few of the suspected objects thus to be erased, and (2) some of those which the future will probably add to our store:-– (1.) (2.)