172 



COMMEMORATION MEETING. 



biologist when speaking of " evolution " are speaking in two 

 different languages. 



The spectroscope proved competent to attack a problem 

 which had seemed for ever beyond our reach, namely the 

 determination of the speed with which a luminous object is 

 approaching or receding from us, and in this way we have 

 learnt that many stars that, even in our most powerful 

 telescopes, appear as single, are really double, the one star 

 revolving rapidly round the other. 



The application of photography to astronomy has immensely 

 increased our knowledge. By means of the photographic 

 plate we have been able to secure the positions of millions of 

 stars, where formerly with the same expenditure of time and 

 trouble we could barely have registered thousands. And from 

 these new sources of information as well as from the further 

 development of old methods, our conceptions of the stellar 

 universe are growing continually in definiteness and 

 magnificence. 



Our old Scandinavian forefathers had their myth of a great 

 Mitgard Snake, the Serpent of the Middle World, which 

 encircled and upheld the universe. The old myth has its 

 counterpart in the astronomical conception of the Galaxy, the 

 convolutions of which encircle the whole sidereal universe so 

 far as we can penetrate it. Stars of different orders of 

 magnitude, stars of specific colours, stars of specific types of 

 spectra, are distributed through space, not at haphazard, but 

 with distinct subordination to the position of the Galaxy. So 

 also with the different orders of nebulae and star clusters. So, 

 more remarkable still, are those evanescent lights which 

 occasionally burst out upon our view, the New or Temporary 

 Stars. 



The stellar universe is therefore one : one in the materials 

 which compose it ; one in the physical laws which condition 

 it ; one in the evident fact that it constitutes a single structure. 

 And the evidence of its unity is bringing us to discoveries more 

 remarkable still. Our conception of the scale of the sidereal 

 universe is continually increasing ; fifty years ago we knew of 

 the distances of but a mere handful of stars ; the nearest being 

 a mere 250 thousand times the distance of the sun, and two 

 million times the sun's distance was the utmost extent of our 

 sounding line into space. Now we have secured indications, 

 subtle and indirect and capable of much modification in the 

 future, that hint at stellar distances one thousand times as 

 great as the most distant which we were able to determine 



