180 PHOTOGKAPHY IIST ASTKONOMICAL RESEARCH. 



longer necessary to have copies of all. This applies, of course, to 

 other publications as well, and though we may take some time to 

 grow out of the sentimental desire for a complete library, and though 

 the existence of a few such complete institutions may always l)e 

 desirable, I venture to think that many observatories will ultimately 

 be driven to the plan of acquiring only what is certainly and imme- 

 diately useful, depending on temporary loans from central institu- 

 tions for other material. 



But there is a class of problems differing totally in character from 

 these practical questions of storage and preservation of plates, A. 

 period of suddenly increased activity such as we have been passing 

 through in astronomy is not without important effects on astronomers 

 themselves. The hunuin element in our scientihc work is sometimes 

 overlooked and generally accorded only a subordinate importance; 

 but, coming as I do from an old imiversity devoted to the humanities, 

 I may be perhaps forgiven for calling attention to a few human con- 

 siderations. In the hrst place, I have felt some anxiety lately for 

 that very imjjortant body of astronomers who are sometimes called 

 " amateurs," though the name is open to criticism — those Avhose 

 opportunities for work are restricted to a more or less limited leisure. 

 It is a body which is somewhat sensitive to the feeling that astronom- 

 ical work has gone bey(md them ; that in the presence of large instru- 

 ments and of the special knowledge acijuired by those using them 

 their own efforts and their own humbler instruments are no longer of 

 any value. If I am right in supposing that this feeling has been 

 called into existence lately by the rapid advances made in photog- 

 raphy, it is certainly not for the fir^t time. At previous epochs this 

 diffidence has found expression, and has. I am glad to say, been met 

 by careful contradiction; but it is necessary to rej)eat the expostula- 

 tion again and again, for the anxiety is ai)t to cro]) up with every new 

 develoi^ment of astronomical activity. 



The earlier days of photogi'a|)hy were better ones than usual foi" 

 the amateur; indeed, the introduction of the phol<)gra2)hic method 

 is largely due to the work of such men as Rutherfurd and Draper in 

 America, De la Kue and Conmion in England. But now that we have 

 passed bej'ond the stage when each new j)late taken was a revelation; 

 now that we are tolerably familiar with, at any rate, the main types 

 of possible ])hotographs which can be taken witli modest apjiaratus; 

 more especially now that we have begun to discuss in elaborate detail 

 the measui'ement of star j)ositions or of stellar s])ectra, the old shyness 

 is begimiing to crop up again. But it is of the utmost importance 

 that this shyness should be /(^alously overccmie. Perha})s, after all, it 

 is not sullicient to assert that there is still good work for amateurs to 

 do, nor even to mention a few instances of such work urgently re- 

 quired ; perhaps it shoidd be made easier for them to follow what is 



