PHILOSOPHICAL SOCIETY OF WASHINGTON. 19 



been felt upon the land where the observer was situated. He 

 alluded to the fact that frequently vessels are seen a short dis- 

 tance from land enjoying winds very different from those pre- 

 vailing on shore ; and further illustrated tlie subject by explaining 

 the local winds observed on either side of the Great Lakes, shown 

 on the Signal Service maps. 



The President spoke of the desirableness that those accustomed 

 to scientific research should note phenomena around them, even 

 at places resorted to for recreation. 



Mr. E. B. Elliott presented 



FURTHER REMARKS ON xMETRIC WEIGHTS AND BALANCES FOR THE 

 POSTAL SERVICE : 



stating that efforts were making, which it was hoped would prove 

 successful, to have the law, which recognized 15 grammes as the 

 equivalent of the half-ounce avoirdupois for postal purposes, 

 applicable not merely for international purposes, but for all pur- 

 poses — domestic as well as international. 



7 iTth Meeting, December 5, 1814. 



The President in the Chair. 

 Forty-three members and visitors present. 

 Mr. H. H. Bates read a paper 



ON THE movement OF A PARTICLE ATTRACTED TOWARDS A POINT. 



(abstract.) 



In this paper it was shown that the ambiguous conclusions 

 heretofore arrived at, in the analytical discussion of the move- 

 ment of a particle attracted towards a point, involving such 

 absurdities as infinite attractive force and infinite velocity, were 

 due to the tacit assumption of want of magnitude in the attracted 

 particle. Said particle, however minute, must be regarded, 

 relatively to a simple attracting point, as a mass or sphere. But 

 Newton has shown that the point of maximum attraction in a 

 homogeneous sphere is not at its centre, but at its surface. The 

 law of attractive force, therefore, changes, when the attracting 

 point penetrates the surface, and, instead of being inversely as 

 the square of the distance, becomes directly as the distance ; that 

 is, a diminishing force, reaching zero at the centre, instead of 



