THE AUGUST METEORS. 



187 



found the shower double at 46 + 57*6^ and 38 + 56 ; and in 1880 

 he strongly corroborated the results obtained at Bristol, though his 

 observations were mainly confined to the night of August 9th. At 

 the latter station the radiant apparently advanced among the stars of 

 Perseus, for, while early in the month it was observed at 38 + 56, it 

 had shifted to 49^ + 57^ by the 13th. The same peculiarity was 

 noted in 1877, when the following determinations were made : 



Radiant. 



7th 40 + 56 



August 10th 43 + 58 



August 3d 



Badiant. 



August 12th 50 + 



August 



65 

 16th 60+59 



There is a prominent display of meteors from the star-group % 

 Persei at the end of July and beginning of August, and it is possible 

 that these showers may belong to the same system of concentric meteor- 

 streams. It is certain that this fact of a progressive radiant requires 

 fuller elucidation, and to this end observers should keep the data ob- 

 tained each night separate. It may also be suggested that the radiant 

 point should be ascertained during each hour of observation, and then, 

 when the series are compared, any displacement must immediately 

 become obvious, and its extent and character well defined by the ob- 

 servations. The meteors from Perseus are so numerous, and the place 

 of divergence so readily denoted by their enduring streaks, that there 

 will be no difiiculty in an investigation of this kind. The last two 

 years' observations have shown how exactly the radiant may be found 

 \)j carefully conducted researches, and how closely the positions de- 

 rived by different observers will agree on being compared together : 



OBSERVER. 



G. L. Tupman 



H. Corder 



E. F. Sawyer. . 

 W. F. Dennin" 



1879, August. 

 Chief Radiant. 



45 + 56 



45 + 57 

 44i H- 57 



46 + 58 



1880, Au^st. 

 Chief Radiant. 



44 + 56 



45 + 58 

 44f + 56i 

 44 4- 56 



From these values a mean of 44'8 + 56-8 is derived, which is 

 probably very near the truth. There is a secondary shower higher in 

 declination (at about 44|^ -f 60), but this is merely a branch of the 

 same stream, for the meteors exhibit the same specialties of appear- 

 ance as those common to the major shower. An apparent diffuseness 

 of the radiant point is often brought about by imperfectly registered 

 tracks, and by allotting the meteors of bordering showers to the 

 radiant of the Perseids, when in fact they belong to evidently distinct 

 families. 



A few years ago the writer undertook the investigation of these 

 co-Perseid showers from the large mass of shooting-stars which had 

 been registered at this epoch at foreign observatories, and are contained 



