ADVERTISEMENT 



In conformity with the established practice of the Institution to 

 obtain the judgment of disinterested experts as to the propriety of 

 accepting Memoirs proposed for the Series of "Smithsonian Con- 

 tributions to Knowledge," the accompanying paper has been 

 referred to a Commission consisting of Professors Simon Newcomb, 

 of the U. S. Nautical Almanac, Thomas C. Mendenhall, of the U. S. 

 Coast and Geodetic Survey, and Mark W. Harrington, of the U. S. 

 Weather Bureau ; and has received their approval and recommendation 

 for publication. 



Washington : December, 1 893. 





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