METEORS AND METEOR SYSTEMS. 
23 
often brilliant ; and in the early evenings of that month, when 
the radiant is at a low altitude, they are extremely conspicuous 
objects with inordinately long courses. The Andromedes of 
November 27 are very slow meteors, and not so brilliant 
generally as the Perseids and Leonids. In fact, the two great 
showers of November are utterly dissimilar in many points, 
though each can boast a parent comet, and each can give a 
periodical display of exceptional grandeur. 
It must be remembered that the appearance of meteors is a 
good deal affected by the position of the radiant points, astro- 
nomically and sensibly. Showers directed from the neighbour- 
hood of the Earth’s apex are characterized by great swiftness 
and enduring streaks, but the non-apical meteors are of less 
speed, according as they recede from the apex, and phosphores- 
cent streaks are rarely seen upon their courses. The position of 
a shower sensibly, and often materially, modifies the distinctive 
features of its members. When the radiant is on the horizon, 
the apparent paths are of extreme length ; but a radiant at great 
altitude, near the zenith, will furnish meteors with short, diving 
courses. These changes are due to the effects of perspective, 
and it is evident therefore that observers should carefully regard 
these facts in determining the real diverging centres of showers, 
for during the same night the meteors of one family undergo 
striking variations as the sensible position of the radiant alters 
its situation with respect to the observer’s horizon. This will 
become apparent at once if the Leonids are watched from their 
rising on the night of November 13. At first the conforming 
meteors are of considerable length, and their flights are some- 
what gradual across the sky ; but just before daylight, when 
the stars of Leo are approaching the meridian, their short, 
darting courses are in singular contrast to the earlier apparitions. 
When the radiant is very low, the visible paths are occasionally 
extended over a vast space of the heavens. On November 12, 
1879, at 10.17 p.m., the writer observed a Leonid (though the 
constellation of Leo was below the horizon) with a path of 98°, 
and this, with a single exception, was the longest track ever 
recorded by him. On December 13, 1876, a meteor was seen 
at 7 h 28 m p.m. with a path of 122° directed from a shower in Leo 
Minor just rising. The average lengths of meteor-paths would 
appear to be about 11°. The mean assigned by Coulvier-Grravier 
is 13° *9. Schiaparelli deduced from Tupman’s observations an 
average of ll o, 0. The writer at Bristol finds 11°*23 from his 
own observations,* and Sawyer at Boston, Mass., gives 9°*8. 
But the mean apparent lengths of the paths are of minor 
importance to the directions of the paths, and it is to be hoped 
* Deduced from 3203 meteor tracks registered in 1876-78. Of 661 
tracks since recorded n 1879, the mean length is 11°*34. 
