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144 believed that his telescope sounded space to this and far greater depths without finding traces of nebulosity—gas or star dust—in the regions it reached. He said also that his telescope sounded the depths of past time not less than of space. Be his ideas reality or romance, they give us a sublime conception of the greatness and worth of the human mind buried in its pigmy house of clay, and chafing against the chains that bind it to earth and time.

Sublime though Herschel's conceptions were, he did not conceal from himself or others that "a certain degree of doubt may be left about the arrangement and scattering of the stars" in the Milky Way. They were founded on the supposition of "numberless stars of various sizes, scattered over an indefinite portion of space in such a manner as to be almost equally distributed throughout the whole." This was a large supposition to make; it is not correct, and it was a corner-stone that might be knocked away at any moment. The barriers he required to overleap were the distance and the relative sizes of the stars. These barriers remained insurmountable during his lifetime. It was next assumed, for it could not be said to be proved, that "there is but little room to expect a connection between our nebula"—the Milky Way—"and any of the neighbouring ones; . . . for if our nebula is not absolutely a detached one, I am firmly persuaded that an instrument may be made large enough to discover the places where the stars continue onwards. A very bright, milky nebulosity must there undoubtedly come on." At that time Herschel imagined space to be a vast ocean of light-bearing ether,