DENISON OLMSTED. 255 



the student that he master and reproduce the lessons conveyed 

 to him. While many lecturers prepare their lectures once for 

 all, and then cease to improve them, he was constantly revis- 

 ing, elaborating, and almost constructing anew the courses on 

 astronomy and meteorology which he delivered annually to the 

 three upper classes." These lectures were spoken of by Dr. 

 Barnard, in his Journal of Education, as having been charac- 

 terized *' by fulness, clearness of method, and sometimes by 

 eloquence. The course on meteorology was, perhaps, on the 

 whole, the most attractive and useful." 



Prof. Olmsted soon became sensible of the deficiency of the 

 text-books on which he had to rely in his department. En- 

 field's Philosophy was inaccurate and behind the state of 

 science ; and the work of Prof. Farrar, of Cambridge, was too 

 extensive and too difficult. He undertook to prepare new 

 books suitable for his classes. His Natural Philosophy ap- 

 peared in 1831, and his School Philosophy in 1832. His As- 

 tronomy, first published in 1839, went through forty or fifty 

 editions. An edition of it was printed in raised letters for the 

 blind, it having been selected by Dr. Howe, according to Dr. 

 Barnard, " for its clear, accurate, comprehensive presentation 

 of the science of which it treats." The Rudiments of Natural 

 Philosophy and Astronomy followed, in 1842. The Letters on 

 Astronomy was a work in more familiar style, cast in the form 

 of letters to a lady, and prepared as a reading book for the 

 school libraries established by the Massachusetts Board of Edu- 

 cation. 



The great meteoric shower of November, 1833, which was 

 observed over a large part of the American continent and on 

 the ocean, directed Prof. Olmsted's mind to a new and original 

 field of investigation ; and several papers upon it were pub- 

 lished by him and Prof. A. C. Twining, of West Point, in the 

 American Journal of Science during 1834. The collation of 

 the collected observations brought out the fact that the appar- 

 ent point of radiation of the meteors was identical with that 

 toward which the earth was tending in space which indicated 

 a cosmical origin. It was further found that several showers 

 had been observed before within forty years, on the same day 

 of November. In explanation of the phenomenon, Prof. Olm- 

 sted supposed, in an article published in the American Journal 

 of Science, that the meteors " consisted of portions of the ex- 



