It is in this way that we receive information from light-waves. It will be conceived how minute they must be, how perfectly they must retain their separate character, multitudinous though they are, in traversing the ether (even when that ether is clogged by the gross matter of our ordinary air), if we remember how through the tiny eye-pupil we often receive light-waves telling us of all the details, all the varieties of colour and brightness, all the movements in a rich landscape. Even more startling are the thoughts suggested by a view of the starlit heavens. From hundreds of suns at once the light-waves which have traversed varying but all enormous distances pour in upon the small circle of the eye-pupil, waves of many kinds coming in together from each sun. The waves which thus reach the eye from one bright star have been but a few years upon their journey; all that time they have been traversing an ocean swept in every part by untold millions of other waves, and yet they arrive as perfect in order and regularity as rollers which have traversed a wide sea pour in upon a level shore. From another star, as bright as the first, they have been years in travelling; from some among the fainter stars, hundreds, perhaps thousands of years. Yet still they flow on, each order of waves in perfect uniformity as when they first left their parent sun. But even this is not all. Among the waves which reach the eye many, nay, most, are so small that ordinary vision cannot perceive their action. Take, however, a telescope, and so gather them together as to intensify this action, and they are rendered perceptible, just as the unnoticed heaving of ocean becomes a manifest wave-motion when it reaches a regularly narrowing inlet. Thus, from stars so remote that their light has required thousands, or, even in some cases, perhaps, hundreds of thousands of years in reaching us, the light-waves flow steadily in upon us. So small are these waves, that the breadth of from forty to sixty thousand of them would occupy but a single inch. Through every point in space waves from all the hundred millions of stars are at all times simultaneously rushing at the rate of one hundred and eighty-five thousand miles in every second of time: yet they travel on altogether undisturbed, and each tells its story as distinctly as though the ether had conveyed no other message, and that message but for a short distance. It would be difficult to say which thought, considered in its real significance, is more striking,--the thought of what is done for us by light regarded as a terrestrial phenomenon, or the thought of what light is doing, and has done, in presenting to us a view of the starlit heavens.