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228 The work of observing, measuring, and recording these worlds of wonder, and sometimes of surpassing beauty even when seen in the magic mirror of a reflector, was enormous: but this indefatigable worker, with his like-minded sister-helper, seemed never to weary in his marvellous efforts to lift the curtain that hid Creation's glories from man. What these glories seemed (to him) to mean was unfolded in 1811 in a memoir, which anticipated by many years the doctrine of evolution taught by Darwin, and which showed the progress, slow it might be, "for, in this case, millions of years are perhaps but moments," but sure, of a vast body of gas condensing into a sun or suns with a train of planets around.

When Herschel entered upon this inquiry he believed that these nebulæ, or whitish clouds or milky ways are clusters of stars, too far off to be resolved into separate points of light, but blended so together as to assume the appearance of a little cloud in the depths of space. "Longer experience and a better acquaintance" with them induced him to change his mind. Vast masses of gas, in which a few stars were sometimes seen, or through which they shone from a greater distance, were believed by him to exist in space, besides those which an increase of telescopic power could resolve, as the phrase was, into stars. It was the idea of a far-seeing mind, feeling its way to truth, and, in our