Speculations so attractive by a watcher with an eye so keen to detect chinks in the armour, that concealed nature's most secret workings, could not fail to be affected by new facts, as they forced themselves on his observation. He found in course of years that "the hypothesis of an equality and an equal distribution of stars is too far from being strictly true to be laid down as an unerring guide in this research. . . . This consideration is fully sufficient to shew that, how much truth soever there may be in the hypothesis of an equal distribution and equality of stars, when considered in a general view, it can be of no service in a case where great accuracy is required." Fifteen years later he wrote: "When we examine the Milky Way, or the closely compressed clusters of stars, this supposed equality of scattering must be given up." It is clear that, until the distance and mutual relations of the fixed stars were ascertained, mere speculations on their size and brilliance were out of place. He found also that Cassini's classification of nebulæ was at least incomplete or defective. He was leaning to the belief that some of the nebulæ are masses of shining gas, while there may be vast masses or regions of it still dark; but these and other matters must be referred to another chapter. It is enough in the meanwhile to say that twenty-five years of further research wrought a change on the views he once expressed. But they also brought into distincter prominence the changeful character of even the starry heavens. They had wrought no change on the awe with which his contemporaries, however trifling they might be, regarded "the profusion of worlds on worlds" revealed to their view. The immense multiplication of life on our
