PREFACE. 



THE computations of the secular inequalities, the results of which are given in 

 the following Memoir, were commenced about ten years ago, and have been con- 

 tinued, during many interruptions, till the present time. In the spring of 1870 

 the calculations were so far advanced that the greater part of the Memoir was 

 put in form for the press ; but funds for printing it were not then available, and 

 the computations were suffered to languish till late in autumn, when provision was 

 made through the Smithsonian Institution for its publication. The work was then 

 resumed, completed, and forwarded to the printer without delay ; but an unex- 

 pected interval of leisure occurring during the process of publication, I availed 

 myself of the opportunity thus presented, and prepared an additional chapter con 

 taining tabular values of the elements of the planetary orbits, together with the 

 formulas necessary for their convenient application. It is believed that this addi- 

 tional chapter will contribute largely to the usefulness of the work, and be found 

 of great practical value in the researches of astronomers. 



J. N. STOCKWELL. 



CLEVELAND, May, 1872. 



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