In attempting to appreciate this interval by the aid of any considerations of _velocity_, as we did in endeavoring to estimate the distance of the moon, we must leave out of sight, altogether, such nothings as the speed of a cannon-ball, or of sound. Light, however, according to the latest calculations of Struve, proceeds at the rate of 167,000 miles in a second. Thought itself cannot pass through this interval more speedily—if, indeed, thought can traverse it at all. Yet, in coming from 61 Cygni to us, even at this inconceivable rate, light occupies more than _ten years_; and, consequently, were the star this moment blotted out from the Universe, still, _for ten years_, would it continue to sparkle on, undimmed in its paradoxical glory. Keeping now in mind whatever feeble conception we may have attained of the interval between our Sun and 61 Cygni, let us remember that this interval, however unutterably vast, we are permitted to consider as but the _average_ interval among the countless host of stars composing that cluster, or “nebula,” to which our system, as well as that of 61 Cygni, belongs. I have, in fact, stated the case with great moderation:—we have excellent reason for believing 61 Cygni to be one of the _nearest_ stars, and thus for concluding, at least for the present, that its distance from us is _less_ than the average distance between star and star in the magnificent cluster of the Milky Way. And here, once again and finally, it seems proper to suggest that even as yet we have been speaking of trifles. Ceasing to wonder at the space between star and star in our own or in any particular cluster, let us rather turn our thoughts to the intervals between cluster and cluster, in the all comprehensive cluster of the Universe. I have already said that light proceeds at the rate of 167,000 miles in a second—that is, about 10 millions of miles in a minute, or about 600 millions of miles in an hour:—yet so far removed from us are some of the “nebulæ” that even light, speeding with this velocity, could not and does not reach us, from those mysterious regions, in less than 3 _millions of years_. This calculation, moreover, is made by the elder Herschell, and in reference merely to those comparatively proximate clusters within the scope of his own telescope. There _are_ “nebulæ,” however, which, through the magical tube of Lord Rosse, are this instant whispering in our ears the secrets of _a million of ages_ by-gone. In a word, the events which we behold now—at this moment—in those worlds—are the identical events which interested their inhabitants _ten hundred thousand centuries ago_. In intervals—in distances such as this suggestion forces upon the _soul_—rather than upon the mind—we find, at length, a fitting climax to all hitherto frivolous considerations of _quantity_.