Page:Sir William Herschel, his life and works (1881).djvu/175

Rh otherwise unknown, from the appearances which are presented by the stars in space.

In this way, acting upon suggestions which had been thrown out previously to his own time by, , and , demonstrated that the sun, together with all its system, was moving through space in an unknown and majestic orbit of its own. The centre round which this motion is directed cannot yet be assigned. We can only know the point in the heavens towards which our course is directed—"the apex of solar motion."

By a study of the proper motions assigned by to the brighter stars,  was able to define the position of the solar apex with an astonishing degree of accuracy. His calculations have been several times repeated with the advantage of modern analytical methods, and of the hundred-fold material now at our disposition, but nothing essential has been added to his results of 1805, which were based upon such scanty data; and his paper of 1782 contains the announcement of the discovery itself. 7*