86 OBSERVATIONS ON THE ORBITS AND VELOCITY OF METEORS. 



whence, for a deviation of 15°, v' must be less than one-third of the earth's ve- 

 locity; that is, far less than either of Erman's supposed values of v' ; and for 

 the least value of v', which Erman has given, namely, 



v' = 0-83122, 

 we have 



^ = 2° 38', 

 which appears to be entirely contrary to a large majority of the observations. 

 Now, for 



v' = 0-33333 = i 

 we find 



m = 14° 10', 2> = -75 = I 

 so that the plane of the meteors cannot differ much from that of the ecliptic, 

 and their relative velocity cannot exceed one-third of the earth's velocity. The 

 other elements of the orbit are of less interest, and I shall not stop to calculate 

 them. A ring so nearly in the plane of the earth's orbit must be subject to 

 very great perturbations, and if there is one, I think that no observations which 

 we can make will enable us to calculate its motions with any degree of ac- 

 curacy. 



Believe me, my dear sir, 



most sincerely yours, 



B.PIERCE. 

 Cambridge, December 24, 1840. 



