METEORS AND METEOR SYSTEMS. 
17 
duration of visibility is thirty days or more, and many instances 
of long duration are similarly evident amongst the extensive 
observations of tbe late Professor Heis. Schiaparelli from the 
reduction of the meteors seen by Zezioli at Bergamo in Italy 
found a series of radiants in the month of January grouped 
together near rj — £ Ursce Majoris , and a Coronce — a JBodtis, and 
in April near t Herculis, and he regarded them as distinct or 
separate families of radiant points, which, though separated 
from each other in position or by nights on which no inter- 
mediate meteors were observed, nevertheless possessed in 
common some features of very close resemblance. ‘ Should 
the effect of planetary perturbations which retarded the return 
of Halley’s Comet in the year 1759, nearly one month from 
the time of its perihelion passage, as calculated by D’Alembert 
and Clairaut, also explain the wide differences between the 
separate coils of spiral meteoric streams apparently encountered 
by the Earth in the meteor- systems of which the above groups 
or families of radiant points appear to present unmistakable 
examples, a new field of investigation in meteoric astronomy 
is beginning to unfold itself in these interesting discoveries.’ * 
In the spring of 1876, the writer commenced a series of 
observations of shooting stars, and they have been continued to 
the present time. The aggregate number of meteors observed 
is 5706, in about 520 hours of watching. The path- directions 
were always registered with special care, the chief aim being to 
derive the radiant points accurately. About half of the total 
number of meteors were recorded before midnight, and the 
remaining half in the morning hours. To supplement and con- 
firm my personal observations, I undertook the reduction of a 
large number of the meteor-paths registered in the foreign 
catalogues of Heis, Weiss, Zezioli, Konkoly, and of the Italian 
Meteoric Association, 1872, and the number thus projected on 
star-charts amounts to more than 13,000. A considerable list 
of radiant points has been founded on this investigation, and the 
results, when compared with other observations, present many 
satisfactory accordances. The long duration of certain showers 
appears to be incontestably proved, for the same radiant points 
became manifested again and again. They cannot be distinct 
streams, supplementing or succeeding each other at short 
intervals from the same general directions, or they would 
exhibit considerable differences in position ; whereas, in the cases 
referred to, the place of departure adheres tenaciously to the 
same exact point of the heavens, so far as it is possible for care- 
ful and prolonged observations to discriminate. The following 
are some of the most prominent examples of these long-enduring 
streams, the average centres of which are derived from a variety 
* B. A. Report , 1871, p. 48. 
NEW SERIES, VOL. IV. NO. XIII. 
C 
