510 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Harvard College Observatory, Volume 19, Part 1, the results, which he 

 had gathered, of the early meteorological observations made at the 

 Observatory from 1840 to 1888. Among these were included various 

 miscellaneous observations relating to the aurora, lightning, meteors, 

 earthquakes, and to some extent to the zodiacal light. 



The zodiacal light was the subject of his first independent investiga- 

 tion. Beginning in 1874 he continued his observations of the zodiacal 

 light and the Gegenschein until 1895, when the increasing use of 

 electricity for street illumination made such work impossible in Cam- 

 bridge. The results of these observations are contained in the 

 Astronomische Nachrichten, Volumes 99, 102, 109, 116, 124, and 126, 

 Proceedings, Volume 19, Memoirs, Volume 11; and the Annals of the 

 Harvard College Observatory, Volumes 19, Part 2, and 33, Nos. 1, 2, 

 and 3. Summaries of information written by him on the subject 

 appear in the Monthly Weather Review and elsewhere. 



The several lines of his inquiry dealt with the permanence, position, 

 and magnitude of the ordinary western zodiacal light; the normal 

 distribution of light in the zodiac and vicinity; and the position, 

 parallax, and brightness of the Gegenschein. His studies led him to 

 favor the hypothesis ascribing the phenomenon to light reflected from 

 small meteoric bodies. He published a statement on the "Meteoric 

 Theory of the Gegenschein" also in the English periodical, Observatory, 

 August, 1899. Although he considered the meteoric hypothesis as the 

 most probable explanation, he felt that his series of observations 

 should be extended to reach a definite conclusion. The research 

 should include the orbital movements and the light of asteroids and 

 periodic comets. He expressed the hope that younger observers more 

 favorably located might carry out his plan. 



In the Observatory he was frequently engaged in the business 

 management, particularly during the interim between Director Win- 

 lock's death and Professor Pickering's appointment. It was at this 

 time that he published Volume 8 of the Harvard Annals, containing 

 his account of the history of the Observatory from 1855 to 1876, with a 

 description of the buildings, instruments and of work done. The 

 volume included also a series of illustrations of Sun, planets, and other 

 celestial objects, which had been drawn mostly by Trouvelot during 

 Winlock's directorship. 



Professor Searle spent ten years — from 1888 to 1898 — in making 



