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