The movements of solar systems through space are unquestionably controlled by some wider law than that of gravitation, and it still remains for science to seek its hidden principles and discover its mode of operation. We know that some stars travel alone, like the star already noted, No. 1830 of Groombridge's catalogue; that others travel in pairs, like the double star Mizar and its companion Alcor; and others in groups, like the stars Beta, Gamma, Delta, Epsilon and Zeta, of the constellation Ursa Major; that we are driving towards the constellation Lyra and leaving behind us Sirius and its fellows, and that many, if not all, of the stars whose motions we can measure have a rapid movement through space, but under what control, in accord with what hidden harmony, and under what general plan they move, we do not know; but the laws of electrical action of the circling planets upon their central suns, and of these upon space, we can readily account for by the similar operation of the same laws within our own solar domain; and we know by the similar terms of the ratio of distribution of light that this is commensurate in extent with the law of gravity, and operates in a like proportion of energy over all intervening distances; so that wherever our sun presents a visible point of light, there it is pouring its energy into space, and every sun we can see, every galaxy, every star-cluster, nay, every nebula, is likewise pouring into the interplanetary space of our own solar system its proportionate quota of energy. The very fact that we can see the star shine is itself the fullest evidence that this is so, and evidence also that the law of gravitation there, too, is still in force, operating over these same distances, and with the same proportionate energy.