ANNIVERSARY ADDRESS. 23 



This question of the solar motion was raised by Halley [1656 — 

 1742], Bradley [1692 - 1762], J. Tobias Mayer [1723 - 1762], and 

 Lambert [1728 - 1777], and the motion itself calculated first by 

 Pierre Prevost 1 in 1781, from the proper motions in Mayer's table. 

 The principle of a new and wholly independent method was con- 

 ceived by Doppler in 1848, and from measurements of radial 

 stellar velocity by Huggins and Seabroke, Horaann in 1885 

 obtained a result roughly agreeing with the earlier deductions 

 from proper motions. The range and scope of modern astronomy 

 will not admit of anything like adequate reference to it : some 

 idea of its extent may be had, however, by referring to the 

 astronomies of Chauvenet, Main, Watson, or Faye, and the 

 Mecaniques Celestes of Resal or Tisserand. 



Apart from the aesthetic interest of this science or its practical 

 value in determining time 2 for us, and in meeting the great require- 

 ments of navigation and geodesy, its work in developing the scale 

 of our conceptions of time, space, and energy, and enhancing the 

 reach of our imagination, can hardly be realized. It would be 

 difficult to estimate how far civilisation depends upon the enlarg- 

 ing of our greater conceptions, but that it does so depend is with- 

 out question. Whatever may be our individual opinion on this 

 matter however, one thing is certain, viz., that the practical assist- 

 ance of astronomy is invaluable ; the commerce of the modern 

 world, in so far as its safety is secured by good navigation, is 

 under great and lasting obligation to the ardent labours of those 

 whose lives have been spent in contemplating the stars, and in 

 interpreting their motions. 



Physics and engineering, which, with practical chemistry, lie 

 immediately behind the material expression of modern civilisation, 



i [1751-1839]. Nouveaux Memoires of the Berlin Academy— R. A. 230° 

 D 25° were the computed coordinates of the point toward which our 

 system moves. 



2 Under the recently established standard time system, every adjusted 

 mean time keeper shews the same minutes and seconds the whole world 

 over. 



