niitliMruiiE Snstitutinn, 



PREFACE. 



For the purpose of facilitating the accurate determination of the geogra- 

 phical position of important points in the United States, the Eegents of the 

 Smithsonian Institution authorized the preparation of lists of occultations 

 and co-ordinates of reduction to particular places for the years 1848 and 

 1849. Congress has, since, ordered the publication of an American JSTautical 

 Almanac ; and, as lists of Occultations will form a regular part of this ephe- 

 meris, Mr. Preston, the late Secretary of the JSTavy, directed that the expense 

 of computing these tables for 1850 should be defrayed from the appro- 

 priation for the almanac — the printing and distribution to be done by the 

 Smithsonian Institution. A similar order has been given by Mr. Graham, 

 the present Secretary of the JSTavy, relative to the tables for 1851 and 1852. 



Copies of these elements will be forwarded to all persons disposed to 

 advance the science of geography, with the request, that the results of the 

 observations which may be made, be sent to the Smithsonian Institution, or 

 published in some accessible scientific journal. 



The following remarks will give a more definite idea of the nature and 

 object of this publication. 



JOSEPH HENKY, Secretary S. I. 



CHARLES H. DAVIS, Superintendent of the Nautical Almanac. 



The present lists of occultations are very much extended by the introduc- 

 tion of occultations visible on any part of the earth. The form of the list 

 is also somewhat altered; that which is now adopted will probably be 

 retained in the astronomical ephemeris. 



