406 THE BEAUTIES OF NATURE CHAP, 
SHOOTING STARS 
On almost any bright night, if we watch a 
short time some star will suddenly seem to 
drop from its place, and, after a short plunge, | | 
to disappear. This appearance is, however, 
partly illusory. While true stars are immense ~ 
bodies at an enormous distance, Shooting Stars 
are very small, perhaps not larger than a pavy- 
ing stone, and are not visible until they come 
within the limits of our atmosphere, by the 
friction with which they are set on fire and 
dissipated. ‘They are much more numerous on 
some nights than others. From the 9th to 
the 11th August we pass through one cluster 
which is known as the Perseids; and on the 
13th and 14th November a still greater group 
called by astronomers the Leonids. © The 
Leonids revolve round the Sun in a period of 
33 years, and in an elliptic orbit, one focus of 
which is about at the same distance from the 
Sun as we are, the other at about that of — 
Uranus. The shoal of stars is enormous; its 
diameter cannot be less than 100,000 miles, 
and: its length many hundreds of thousands. 
P —T — ~~ sr | 
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