344 A SHORT HISTORY OF SCIENCE 



vations and calculations they discovered the relatively simple laws 

 of the motions of the heavenly bodies, whose invariable and exact 

 fulfilment led to the belief that the whole universe in all its parts 

 is orderly and that science is possible. In the modern world this 

 conclusion is so commonplace that its immense value is apt to be 

 overlooked, but a study of the superstitions and the hopeless stagna- 

 tion of those portions of mankind which have not yet made the dis- 

 covery gives us some measure of its worth. The modern supplement 

 to the conception that the universe is not a chaos is that not only is 

 it an orderly universe at any instant, but that it changes from one 

 state to another in a continuous and orderly fashion. This doctrine 

 that science is extensive in time, as well as in space, is the funda- 

 mental element in the theory of evolution and the completion of the 

 conception of science itself. The ideas of evolution in a scientific 

 form were first applied to the relatively simple celestial phenomena. 

 More than a century before the appearance of Darwin's 'Origin of 

 Species,' and the philosophical writings of Spencer, another English- 

 man, Thomas Wright; published a book on the origin of worlds. La- 

 place's nebular hypothesis gave the geologists a basis for their work, 

 which in turn paved the way for that of Darwin. For half a century 

 now, the doctrine of evolution has been a fundamental factor in the 

 elaboration of all scientific theories, and its influence has spread to 

 every field of intellectual effort. It has been the good fortune of 

 mankind that his skies have sometimes been free of clouds and that 

 he has been able to observe those relatively simple yet majestic and 

 impersonal celestial phenomena which have not only led to so im- 

 portant results as the founding of science and the doctrine of evolu- 

 tion, but have strongly colored his poetry, philosophy and religion, 

 and have stimulated him to the elaboration of some of his most pro- 

 found mathematical theories. Moulton. 



DISTANCE OF THE STARS. Among other astronomical dis- 

 coveries bearing a notable relation to the history of mathematical 

 science is that of measurable stellar parallax by Bessel (1784- 

 1846). One of the traditional objections to the Copernican theory 

 had been the fact that no change could be detected in the relative 

 position of the stars, such as would apparently result from revolu- 

 tion of the earth in a vast orbit. Now with more and more 

 powerful instruments it turned out that there were stars near 



