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PIONEERS OF SCIENCE IN AMERICA. 



years, and then induced our well-known colleague, Mr. Downes, 

 to undertake the continuance of the work. It has been prose- 

 cuted to the present time, with what success we all know, and 

 has of late years been published by the Smithsonian Institution 

 and the Astronomical Ephemeris. Astronomy and geography 

 in America are much indebted to Mr. Walker for these labours, 

 since many already in possession of the necessary means were 

 stimulated by the periodical announcements, and by his per- 

 sonal exertions in still other ways, direct and indirect, to ob- 

 serve these phenomena. An extensive series of such observa- 

 tions was collected by Mr. Walker and published in the Proceed- 

 ings of the American Philosophical Society." 



During most of Walker's residence in Philadelphia he must 

 be regarded as an amateur rather than a scientist. For many 

 years his interest in Nature was spread over several fields, but 

 gradually it concentrated upon astronomy. He had procured 

 an astronomical clock, a twenty-inch transit instrument, and a 

 small Dollond telescope, and from about the time when he 

 gave up his school to become actuary of the insurance com- 

 pany all his leisure was devoted to astronomical observation 

 and study. "In 1837," Dr. Gould's account continues, "he 

 was invited to propose a plan for an observatory in connection 

 with the Philadelphia High School, an invitation which he ac- 

 cepted with eagerness. In accordance with his suggestion, the 

 committee in charge of the school imported from Munich the 

 excellent Fraunhofer equatorial and Ertel meridian circle 

 which, in his hands and those of his accomplished brother, the 

 present director of the observatory, have done so much for 

 astronomy in America not merely by the number of observa- 

 tions made with them, but also by the incentive which they 

 afforded to the lovers of astronomy in other parts of the coun- 

 try. It is unquestionable that in several instances they in- 

 duced successful efforts for the procurement of similar and 

 even superior apparatus elsewhere." The results of Walker's 

 researches appeared from time to time in the publications of the 

 American Philosophical Society and various journals. It was 

 in 1841 that he may be said to have " earned his spurs " by a 

 paper on the periodical meteors of August and November, 

 which for many years remained the most important memoir on 

 the subject that had appeared. From that time on he is to be 

 ranked among scientific investigators. 



