90 REPORT— 1872. * 



projected upon separate maps. A similar projection of the paths of the 

 meteors recorded at the Royal Observatory at Greenwich on the night of the 

 10th of August was also made upon a separate map for each interval of ten 

 minutes during the hours of observation. With the exception of the period 

 between 9^ and 10" p.m. on the 10th among the Greenwich observations, and 

 between 9'' 45" and 10'' 45" p.m. on the same evening among those of the 

 British-Association observers, when 40 per cent, of all the meteors mapped 

 diverged very accurately from a centre of radiation at about E. A. 34°, N. 

 Decl. 61° nearly midway between ^ Persei and t Cassiopeise, and a very 

 marked activity of this radiant-point during the following hours of both those 

 scries of observations until midnight on the 10th, no tendency to accurate 

 divergence from a single radiant-point during any sustained jieriodwas obser- 

 vable during the continuance of the shower. A radiant-point near rj Persei, 

 which was also discernible among the British-Association observations on each 

 evening of the shower, presented itself most conspicuously in those made at 

 Greenwich on the evening of the 10th, towards midnight, and by the inter- 

 section of its meteor-tracks with otliers from the more northern radiant, 

 appeared to give rise to a prominent centre of divergence after midnight 

 between y and e Cassiopeiaj, which may have owed its apparent activity to 

 the simultaneous existence of the former pair. The general radiant-point of 

 the meteoric shower at Greenwich on the night of the 10 th was very nearly 

 the principal one already indicated, with a tendency, especially after midnight, 

 of some meteors to come from directions nearer to n and to y Persei. All 

 the meteor-tracks noted by the British-Association observers between 9^ 30"" 

 and 12'M4" on the 10th having been projected upon a single map with the 

 radiant-point in Perseus near the centre of the projection, a densely crowded 

 region of intersection of the tracks prolonged backwards was found to occupy 

 a roughly triangular space of about 10° in length along each side, having its 

 centre very nearly at the above indicated spot in li. A. 36°, N". Decl. 58°, and 

 its angles in nearly symmetrical positions at points in E. A. 31°, N. Decl. 61°, 

 R. A. 36°, N. Decl. 53°, and R. A. 45°, N. Decl. 50°, as shown by the small 

 circles marked (lo) in the accompanying figure. The first of these points cor- 

 responds very closely with the definite radiant-point, which was most conspi- 

 cuous during the early portion of the shower. 



On the night of the 11th the principal intersection of meteor- tracks recorded 

 at the Royal Observatory, Greenwich, was still close to the latter point, at 

 R. A. 31°, N. Decl. 62°, during the hours of observation from 9" until 13" 30'", 

 with subordinate points of intersection at B and D Camclopardi, and between 

 »j and P Persei. A projection of all the tracks recorded by the British-Asso- 

 ciation observers between 9" 45™ and 13" on this night having been made on 

 a similar map to that prepared for the observations of the 1 0th, the principal 

 centre of divergence was found to be placed not far from its position on the 

 previous night, a few degrees northward from j^ Persei, at R. A. 31°, N. 

 Decl. 58°. A meteor with very short course appealing close to this point 

 marked its position very nearly. The tracks of the remaining meteors were 

 almost evenly distributed round it, within distances which included nearly all 

 the courses of 12° or 15° from its centre. But other apparent centres of radia- 

 tion also presented themselves somewhat definitely near the north and south 

 borders of the radiant-region, in the neighbourhood of e Cassiopeiae and r) Persei, 

 at points in R. A. 25°, N. Decl. 63°, and R. A. 42°, N. Decl. 55°, as shown 

 in the figure by the small circles marked (u), forming apparent outliers of the 

 central point. 



