I quoted, just now, from Sir John Herschell, the following words, used in reference to the clusters:—“On one hand, without a rotary motion and a centrifugal force, it is hardly possible not to regard them as in a state of _progressive collapse_.” The fact is, that, in surveying the “nebulæ” with a telescope of high power, we shall find it quite impossible, having once conceived this idea of “collapse,” not to gather, at all points, corroboration of the idea. A nucleus is always apparent, in the direction of which the stars seem to be precipitating themselves; nor can these nuclei be mistaken for merely perspective phænomena:—the clusters are _really_ denser near the centre—sparser in the regions more remote from it. In a word, we see every thing as we _should_ see it were a collapse taking place; but, in general, it may be said of these clusters, that we can fairly entertain, while looking at them, the idea of _orbitual movement about a centre_, only by admitting the _possible_ existence, in the distant domains of space, of dynamical laws with which _we_ are unacquainted. On the part of Herschell, however, there is evidently _a reluctance_ to regard the nebulæ as in “a state of progressive collapse.” But if facts—if even appearances justify the supposition of their being in this state, _why_, it may well be demanded, is he disinclined to admit it? Simply on account of a prejudice;—merely because the supposition is at war with a preconceived and utterly baseless notion—that of the endlessness—that of the eternal stability of the Universe.