576 The Smithsoniaii Institution 



LIST OF OCCULTATIONS VISIBLE IN THE 

 UNITED STATES, AND ELSEWHERE 



At the date of the foundation of the Smithsonian Institution 

 (1846) the vast territory west of the Mississippi River was 

 unmapped, and, in a large measure, unknown. One of the 

 first practical duties of astronomers was to take scientific 

 possession of it — to determine the latitude and longitude 

 of points within it which would serve as origins for detailed 

 surveys.^ 



The great precision of longitudes determined by obser- 

 vations of occultations was early recognized by American 

 astronomers,^ and from the year 1848 onwards, lists of such 

 phenomena were printed and distributed by the Smithsonian 

 Institution. The calculations and tables were made by Mr. 

 John Downes, and his results were of great service to the 

 officers of the United States Coast Survey, to the topograph- 

 ical engineers of the Army, and to other explorers and sur- 

 veyors. They were especially useful in the newly-acquired 

 territory on the Pacific Coast. 



Faithful to its general and wise policy, the Institution 

 carried on the preparation and publication of these tables 

 until the establishment^ of the ** American Ephemeris" enabled 

 a transfer of this responsibility to be made to other competent 

 hands. 



1 " When we consider the character and 2 Occultations were regularly observed at 



condition of the vast Continent of North Harvard College Observatory during the 



America, which it belongs to us chiefly to years 1846 to 1850. See " Memoirs of Anier- 



reduce to a habitable and civilized state, ican Academy of Arts and Sciences, Second 



we shall perceive that the practical scien- series," Volume iii, 1848. 



tific explorer has no higher duty than to 3 The preparation of the " American Ephe- 



settle the geography, the magnetism, the meris " was begun in 1849, and the theoreti- 



natural history, and the climate of these cal portion of the work w.as placed under the 



regions." — "Smithsonian Report," 1852, direction of Benjamin Peirce, of Harvard 



page 237. University. 



