The principal results contained in the following report were communicated 

 to the National Academy of Sciences, and the report in full was after- 

 wards presented for publication to the Smithsonian Institution by the author, 

 Dr. B. A. Gould, with the consent of Prof. Benjamin Peirce, Superintendent 



of the Coast Survey. 



JOSEPH HENRY, 



Secretary S, I. 



Smithsonian Institution. 

 October, 1869. 



(iii) 



