Some astronomers even believe the sudden cold-
ness often observed in the months of February and
May is caused by meteoric rings passing between us
and the sun. These bodies descend nearly to the
summits of our high mountains sometimes, and travel
at a very rapid rate, some say thirty-five miles a
second y this fearful speed causes their incandescence
when they get within the range of our atmosphere,
and most of them proceed on their journey through
space after they have given us a glimpse of their
brightness.
Some of them, however, turn to vapour, and some
prove rather more troublesome visitors, for, being
acted on by the power of gravitation, they fall to the
surface of our earth, and sometimes do great damage.
Bolides are round bodies of the same natiure ; thej
also make a sudden appearance in our atmosphere
sometimes lighting up the landscape with a blue ligl
more brilliant than moonlight, sometimes they e
plode with a loud noise that might be mistaken \
celestial artillery. They often leave a glowing stre



A JO URNEY THROUGH SPA CE. 95

of light behind them. Bolides are rather rare ; not
more than a thousand have ever been recorded.
Many instances of the fall of meteorites are related ;
they are always stony and metallic masses, and
seem at one time to have been in a state of fusion ;
perhaps those who imagine nebula to be the * germ
of which worlds are made/ may imagine meteoric
masses to be the burnt ruins of destroyed worlds.
