SKETCH OF PROFESSOR EDWARD S. II OLDEN. 115 



Statistics of American Soldiers," published by the United States Sani- 

 tary Commission, and in the same year he graduated with distinction 

 from the Scientific School, receiving the degree of B. S. While at 

 the university he also went over an important part of the classical 

 course. 



With a view of continuing his mathematical studies, he secured 

 an appointment to the Military Academy at West Point through 

 the Hon. J. W. McClurg, Representative of the Fifth Missouri Dis- 

 trict in Congress, and was admitted as a cadet to the Academy on 

 the 1st of September, I860. On the 15th of June, 1870, he was 

 graduated, third in a class of fifty-nine members, and was appointed 

 Second-Lieutenant of the Fourth United States Artillery. He was 

 assigned to Company G of that regiment, and served with his com- 

 mand at Fort Johnston, North Carolina, until August, 1871, when 

 he was ordered to duty at the Military Academy, West Point, as 

 Assistant Professor of Natural and Experimental Philosophy. June 

 10, 1872, he was transferred to the Engineer Corps of the army, 

 remaining at West Point, however, as instructor in practical military 

 engineering. 



During these few years at the Military Academy he published, in 

 the "American Journal of Science," his first astronomical work — a 

 short paper on the " Spectrum of the Aurora " and another on the 

 " Spectrum of Lightning." 



In March, 1873, Lieutenant Holden resigned his commission in the 

 army, and was appointed Professor of Mathematics in the United 

 States Navy, a position which his teacher Chauvenet had held before 

 him. He was ordered to the Washington Naval Observatory, then 

 under the direction of Rear- Admiral B. F. Sands, and his first duties 

 in his new profession were as assistant to Professor Harkness in the 

 work of the transit circle. Immediately, however, upon the comple- 

 tion and mounting of the twenty-six-inch equatorial — at that time the 

 largest refractor in the world — he was transferred, November 15, 

 1873, to duty as assistant to Professor Newcomb, who had been 

 placed in charge of that instrument. 



The results of Professor Holden's work during six years of obser- 

 vation with this instrument, first as assistant to Professor Newcomb, 

 and afterward as assistant to Professor Hall, have been printed in 

 the volumes of the Observatory publications and in various astro- 

 nomical journals. Turning over the files of the " Astronomische 

 Nachrichten" for these years, we find numerous observations of 

 comets and of double stars, of the satellites of Uranus and Neptune, 

 and of the companion of Sirius ; but, besides all this rather prosaic 

 routine work, Professor Holden devoted himself zealously to the more 

 fascinating study of the physical features of the planets and nebu- 

 lae. His most elaborate investigation in this field is given in the 



