Minute and scattered far apart as the planets of the solar system appear when thus represented, yet the solar system is a compact little group when we come to consider the distance from it of the other suns—the “fixed stars,” which exist literally in millions beyond it. The nearest of these stars (its name is Alpha Centauri) is no less than three light-years distant from us. A light-year is five and a half billion (that is, five and a half million million) miles. The nearest sun to us after our own sun is, therefore, about sixteen billion miles away, and if its light were suddenly extinguished, we should not know of its extinction for three years. How many—we may well ask—how many of these fixed stars—suns like our own—are there? Roughly speaking, we can see with the naked eye, reckoning both the northern hemisphere and the southern together (for the stars seen from the former are other than those seen from the latter), about 8000. Not many after all, one is inclined to say. But stop a minute and hear what the telescope reveals. With the best telescope about one hundred million can be seen, less and less brilliant and more difficult to see in proportion to their remoteness. And now we go further even than that. For within the last thirty years the great science of astronomy has been rejuvenated by the application of photography to its task. The invention of the “dry” plate, a sensitive photographic plate which does not spoil by prolonged exposure as the “wet” plate does, enables the astronomer to keep his telescope fixed by slow-moving clockwork on to a given region of the sky for four or five hours or more, and the very faint stars, invisible by the aid of the most powerful telescope—stars the light from which is so feeble that it could not affect the plate in a few seconds or minutes, have time by the continued action of their faint light to print themselves on the plate and sign, as it were, a definite record of their existence for man to see and measure, though they are themselves for ever invisible to his eye. It is not possible to say how many may be recorded in this way by photography; it depends on length of exposure. But some thousands of millions of stars can certainly be so recorded. These “unnumbered hosts” are of various degrees of brightness, and by methods which astronomers have invented, but cannot be described here, it is actually known how they differ in size from one another (many are far bigger than our sun), and with some approach to certainty, how far off they are. Stars of four, five, ten, and more “light-years” away from us are well known. Astronomers actually estimate the decreasing abundance in space of stars as one passes from a sphere or spatial envelope of fifty light-years’ distance to one of 250 light-years. Finally, reasons have been given of late for considering many of the “photographic” stars to be at a distance of 32,000 light-years. I will not produce the awful figure in