JAMES EDWARD KEELER. 89 



affording them every possible encouragement to continue along the 

 same lines, Professor Keeler arranged to devote his own observing time 

 to the Crossley reflector. He recognized that the instrument was not 

 in condition to produce satisfactory results. He made one change after 

 another, overcoming one difficulty after another, until, on November 

 14, he secured an excellent negative of the Pleiades, and on November 

 16 a superb negative of the Orion Nebula. The enormous power of the 

 reflector in nebular photography was established, and he entered upon 

 the program of photographing all the brighter nebulae in Herschel's 

 catalogue. More than half the subjects on the program have been 

 completed. The observatory possesses a set of negatives of the principal 

 nebulae which is priceless and unequaled. These photographs have 

 already led to many discoveries of prime importance; and they furnish 

 a vast amount of material for future investigations of questions bearing 

 especially upon the early stages of sidereal evolution. The photographs 

 record incidentally great numbers of new nebulae — as many as thirty-one 

 on a single plate covering less than one square degree of the sky. A 

 conservative estimate places the number within reach of the Crossley 

 reflector at 120,000, of which only ten or fifteen thousand have thus 

 far been discovered. 



It had previously been supposed that the great majority of nebulae 

 were irregular and without form, and that only a few were spiral. 

 Professor Keeler's photographs have recorded more spiral nebulae than 

 irregular ones. This discovery bears profoundly on theories of cosmog- 

 ony, and must be considered as of the first order. 



It is time to refer to Professor Keeler's work as director. I but 

 faintly reflect the views of every member of the staff, and indeed of all 

 who have been interested in the work of this observatory, when I say 

 that his administration was completely successful. He cherished and 

 promoted ideal conditions in this ideal place. He made a success of his 

 own work in a splendidly scientific manner, and he saw to it that 

 every one had all possible opportunities to do the same. No member of 

 the staff was asked to sacrifice his individuality in the slightest degree. 

 Nor were demands made for immediate results: no one's plans were 

 torn up by the roots to see if they were growing. The peace of mind 

 of the investigator, so absolutely essential for complete success, was 

 full and undisturbed. Withal, Professor Keeler's administration was 

 so kind and so gentle — and yet so effective — that the reins of govern- 

 ment were seldom seen and never felt. 



The elements of his successes are simple and plainly in view. His 

 openness and honesty of character, his readiness and quickness to see 

 the other man's point of view, his strong appreciation of the humorous 

 as well as the serious, and above all, his abounding good sense — 

 these traits made his companionship delightful and charming. Scien- 



