PRESIDENTIAL ADDRESS, B.A. 1871. 193 



the inclination of the orbit's plane to the plane of 

 the ecliptic. The orbit which he thus found agreed 

 so closely with that of Tempel's Comet I. 1866 

 that he was able to identify the comet and the 

 meteoric belt 1 . The same conclusion had been 



1 Signer Schiaparelli, Director of the Observatory of Milan, who, 

 in a letter dated 3 1st December, 1866, pointed out that the elements 

 of the orbit of the Augtcst meteors, calculated from the ob- 

 served position of their radiant point on the supposition of the 

 orbit being a very elongated ellipse agreed very closely with those of 

 the orbit of Comet II., 1862, calculated by Dr. Oppolzer. In the 

 same letter Schiaparelli gives elements of the orbit of the November 

 meteors, but these were not sufficiently accurate to enable him to 

 identify the orbit with that of any known comet. On the 2 1st 

 January, 1867, M. Leverrier gave more accurate elements of the 

 orbit of the November meteors, and in the Astronomische Nach- 

 richlcn of January 9, Mr. C. F. W. Peters, of Altona, pointed out 

 that these elements closely agreed with those of Tempel's Comet (I. 

 1866), calculated by Dr. Oppolzer, and on February 2, Schiaparelli 

 having recalculated the elements of the orbit of the meteors, himself 

 noticed the same agreement. Adams arrived quite independently 

 at the conclusion that the orbit of 33^ years period, is the one 

 which niiisCkQ chosen, out of the five indicated by Prof. Newton. 

 His calculations were sufficiently advanced before the letters referred 

 to appeared, to show that the other four orbits offered by Newton 

 were inadmissible. But the calculations to be gone through to 

 find the secular motion of the node in such an elongated orbit as that 

 of the meteors, were necessarily very long, so that they were not 

 completed till about March 1867. They were communicated in 

 that month to the Cambridge Philosophical Society, and in the 

 month following to the Astronomical Society. 



VOL. II O 



