THE FUNCTION OF LARGE TELESCOPES. 137 



question, "Do large telescopes pay?" it is simply a matter of deter- 

 mining whether the work which can not be done without the aid of such 

 telescopes is really worth doing. No one who is familiar with this work 

 is likely to deny that it is worth all the money and time and labor that 

 can be devoted to it. I therefore confidently believe that the generous 

 benefactions which during the last quarter century have permitted the 

 erection of large telescopes in various parts of the world have beeu 

 wisely directed, and that further sums might well be expended, partic- 

 ularly in the Southern Hemisphere, in the establishment of still more 

 powerful instruments. 



