Proceedings of the American Philosophical Society. 53 



method employed in observing; by which a greater proportion of the 

 meteors seen was marked unconfoi^mable, and excluded from the general 

 estimate. 



Mr. Walker referred to some of the analytical conclusions drawn by 

 Mr. Erman* from the fact, which the Philadelphia observations of this 

 year go to confirm, that these meteors appear to converge nearly to a 

 common point in the heavens. 



" 1st. Mr. Erman concludes, that these bodies are of a cosmicdl origin; 

 that they move in a continuous ring-formed stream, of not less than 3° in 

 breadth ; that the plane of the center of this stream is inclined at least 

 56°, probably more than iO°, and not exceeding 124°, to the plane of the 

 ecliptic, — an inclination which hitherto comets alone have been known to 

 possess. 



"2d. That their least velocity in space Aug. 10.5th, is 55 hundredths 

 that of the earth in its orbit, giving them a period round the sun of 128 

 days; that their greatest velocity is 143 hundredths that of the earth, 

 which would locate them at this time on the perihelion of a parabola or 

 ellipse of period indefinitely great. 



" 3d. That to remove this uncertainty of their velocity, between 55 

 and 143 hundredths that of the earth, it is only necessary that two ob- 

 servers, at a distance apart, should trace with precision the apparent path 

 of the same meteor, and one of them at least its duration. This condi- 

 tion had not yet been fulfilled in Europe, otherwise the entire elements of 

 their orbit would have been approximately determined. 



"4th. That their perihelion. distances are not less than 2 hundredths 

 nor more than 97 hundredths of the earth's mean distance from the sun. 



Astr. Nachr., Nos. 385, 390, and 404. 



