21 



nitely great. The author also remarks, that the quantities neglected 

 in Prof. Erman's formula) for this motion, -may produce an important 

 effect on the result, and even change its direction from a retrograde 

 motion, as found by Prof. Erman, to a direct motion as observed by 

 Mr. Fitch, at New Haven, and as indicated by Prof. Forshey.'s ob- 

 served positions of this point at two different dates on the night of 

 10th August last. A slight anachronism is also mentioned in Mr. 

 Walker's oral communication, Mr. Hcrrick having called the atten- 

 tion of observers to the August period, after the display of 1837, in- 

 stead of before; Mr. H. having made no observations that year him- 

 self, but having reported the convergent as observed about 30 degrees 

 from the pole in the Camelopard, by Mr. ShaefFer, of New York. 



The same committee, to whom had been referred a commu- 

 nication from Professor Pierce, of Cambridge, Mass., contain- 

 ing: remarks on Mr. Erman's discussion of the orbits of the 

 periodical meteors, and an investigation of their perturbations, 

 reported in favour of publishing the communication in the 

 Transactions; and its publication was thereupon ordered. 



The paper has reference to the earth's attractive force in increasing 

 the relative velocity of a meteor approaching near its surface. The 

 formulae employed are those of the Mec. Cel., Vol. IV., Book 9, 

 Chap. 2 ; the meteor being at the time within the earth's sphere of 

 activity, the radius of which is 0.0053 in units of the earth's mean 

 distance, the actual radius vector being 0.0057, for the date in 

 question, August 10th, 1839. The notation is that of Prof. Erman, 

 Jr., in Schumacher's Astr. Nachr., No. 385. If v' 2 denote the me- 

 teor's relative velocity in its elliptic orbit round the sun, according to 

 the cosmical theory adopted by Professor Erman, then according to 

 Professor Pierce, the square of the actual relative velocity increased 

 by the earth's attraction is, «,' 3 = v' 2 -f- 0.13932, in units of the 

 earth's true tangential velocity. Professor Erman, having com- 

 prised within certain limits the possible true and relative velocities of 

 the meteors, from the sun's central force; these, together with the in- 

 creased relative velocity, are thus pointed out. The author, however, 

 states, that Prof. Erman's minimum limit of the relative velocity is 

 adopted on insufficient ground, owing to the rejection of one of the 

 two roots of an equation of the second degree, where both roots are 

 possible. A similar remark is applied to Prof. Erman's limits for the 

 inclinations and other elements of the meteor's orbits. The author 

 then gives the reasons which tend to show that the actual rela- 



