1889.] On the Spectra of Meteor-swarms. 387 



a. Cygni. All Hues except those of hydrogen are rather faint. F is 

 the thickest line, G could not be seen very well, but C was well 

 visible. D is fairly strong in comparison with 6 or E. E seems a 

 little fainter than 5, but stronger than the other members of the trio. 

 579 and 568 are seen, the former being much the stronger ; it is 

 almost as strong as D. The line near 499 is not very strong, and 

 there appears to be a line on each side of it. The faint lines near 546 

 and 558 are also visible. 



7 Cygni. The lines are much easier to see and much more numerous 

 than in a Cygni, although the whole spectrum is very much fainter. 

 F is thicker than in a Cygni, and G is also visible. D and b are about 

 equal in intensity, E is about the same as D, but much stronger 

 than the other members of the trio. 579 is nearly as strong as E, but 

 much stronger than 568. 499 is faint but certainly present. The 

 lines near 546 and 558 are also present. 



Cygni. All the lines except those of hydrogen are faint. F and 

 G are thicker than in 7 Cygni, and therefore thicker than b or E, 

 whilst E is thicker than the other members of the trio. 579 is a 

 little stronger than 568. 499 and the lines near 546 and 558 are 

 about equal, but very faint. 



/3 Persei. All lines faint with the exception of those of hydrogen. 

 F and G both thick. &, D, and E are about equal in intensity. The 

 remaining two members of the trio are also as thick as E. 579 is 

 present, but 568 could not be seen. There is also a line near G, about 

 450; it is seen in the Henry Draper Memorial photograph of the 

 spectrum of this star as a double, but it could not be resolved with 

 the power used. 



a. Aquilce. All lines very faint except those of hydrogen. F and 

 G very thick. 6, D, and E very faint but about equal in intensity. 

 579 is not quite so strong as D. 499 is fairly well seen, as are also the 

 two lines near 546 and 558. 



x Lyrce. All the lines except those of hydrogen are exceedingly 

 faint. F is very strong but G is not quite so thick. & and D are fine 

 lines, and about equal in intensity. The trio is undoubtedly present 

 as also the lines near 546, 558, and 579. 



The results of the observations which have been referred to are 

 embodied in fig. 1. The star at the lowest temperature is on the 

 lowest horizon, and the one at the highest temperature is on the top 

 horizon. The thicknesses of the lines have been greatly exaggerated 

 in the diagram, in order to render the variations more obvious. 



