comparison, what are we to think of a collection in which these objects are enumerated in thousands?  In this great catalogue we find arranged in systematic order all the nebulae and all the clusters which had been revealed by the diligence of the Herschels, father and son, in the Northern Hemisphere, and of the son alone in the Southern Hemisphere.  Nor should we omit to mention that the labours of other astronomers were likewise incorporated.  It was unavoidable that the descriptions given to each of the objects should be very slight.  Abbreviations are used, which indicate that a nebula is bright, or very bright, or extremely bright, or faint, or very faint, or extremely faint.  Such phrases have certainly but a relative and technical meaning in such a catalogue.  The nebulae entered as extremely bright by the experienced astronomer are only so described by way of contrast to the great majority of these delicate telescopic objects.  Most of the nebulae, indeed, are so difficult to see, that they admit of but very slight description.  It should be observed that Herschel’s catalogue augmented the number of known nebulous objects to more than ten times that collected into any catalogue which had ever been compiled before the days of William Herschel’s observing began.  But the study of these objects still advances, and the great telescopes now in use could probably show at least twice as many of these objects as are contained in the list of Herschel, of which a new and enlarged edition has since been brought out by Dr. Dreyer.

One of the best illustrations of Sir John Herschel’s literary powers is to be found in the address which he delivered at the Royal Astronomical Society, on the occasion of presenting a medal to Mr. Francis Baily, in recognition of his catalogue of stars.  The passage I shall here cite places in its proper aspect the true merit of the laborious duty involved in such a task as that which Mr. Baily had carried through with such success:—­

“If we ask to what end magnificent establishments are maintained by states and sovereigns, furnished with masterpieces of art, and placed under the direction of men of first-rate talent and high-minded enthusiasm, sought out for those qualities among the foremost in the ranks of science, if we demand QUI Bono? for what good a Bradley has toiled, or a Maskelyne or a Piazzi has worn out his venerable age in watching, the answer is—­not to settle mere speculative points in the doctrine of the universe; not to cater for the pride of man by refined inquiries into the remoter mysteries of nature; not to trace the path of our system through space, or its history through past and future eternities.  These, indeed, are noble ends and which I am far from any thought of depreciating; the mind swells in their contemplation, and attains in their pursuit an expansion and a hardihood which fit it for the boldest enterprise.  But the direct practical utility of such labours is fully