36 PROCEEDINGS OF THE AMERICAN ACADEMY 



vations, and are probably the most accurate predicted star-positions 

 in existence. They have been made the standard in the Memoir now 

 laid before the Academy, ' 



Professor Peirce made the following brief communication, — 



On the Lunar Bolis. 



In a memoir by the illustrious Plana " on the motion of the centre 

 of gravity of a solid body, thrown towards the earth, between the cen- 

 tres of the moon and the earth, which are supposed fixed in space di- 

 rectly after the impulse," the attention of geometers is drawn to the 

 hypothesis of the lunar origin of the bolis. This memoir deserves to 

 be studied for its interesting mathematical developments. But the 

 limitations of the problem, arising from the immobility of the moon 

 and earth, remove the solution quite far from the case of nature. And 

 yet it would seem that, in its unlimited form, the problem was beyond 

 the powers of analysis. This is indeed the case, theoretically ; but 

 practically, the solution is greatly simplified by giving the moon its 

 proper motion relatively to the earth. 



The reason of this practical simplification is not difficult to perceive. 

 The path of the bolis which actually comes from the moon to the earth 

 must differ very little from a straight line ; and it is only in the imme- 

 diate vicinity of the moon that there can be any sensible motion per- 

 pendicular to the radius vector drawn to the earth. When the bolis 

 leaves the sphere of the lunar action, then its velocity must be almost 

 wholly in the direction of the radius vector drawn to the earth. A 

 careful and critical analysis fully confirms this inference, which was 

 indeed the basis of Dr. Gould's memoir upon the lunar origin of the 

 aerolites, which was read at the Springfield Meeting of the American 

 Association for the Advancement of Science, and establishes the con- 

 clusions of that original and able memoir. 



Five Iinndred and thirteentli meeting, 



October 14, 1862. — Monthly Meeting. 



The President in the chair. 



The Corresponding Secretary presented the following botan- 

 ical papers : — 



