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PROCEEDINGS OF THE AMERICAN ACADEMY 



marked, " must be regarded mechanically as a system of for- 

 ces or powers which is a perfect representative of all the single 

 powers of which the system is compounded, and this, too, at 

 whatever time or times the component powers may have been 

 introduced into the system. The question of the simulta- 

 neous introduction of the partial powers is of no importance. 

 Any power which is at any time communicated to the system 

 is preserved in the system unchanged in amount or direction." 

 Dr. B. A. Gould, Jr., presented a discussion of the observa- 

 tions of the planet Metis, with a determination of its orbit, ac- 

 companied by a computation of the subsequent perturbations 

 of the orbit, and an ephemeris. 



" All observations known to me have been used, with the exception 

 of a few extra meridional ones at times when meridian observations 

 were numerous. They are as follows, — corrected for parallax and 

 reduced to Berlin mean time and decimals of a day. 



" Observations of Metis, 1848. 



