TO KNOW THE STARRY HEAVENS 
39 
will average about one each minute, or 
even more. Each one is merely a little 
cold particle, or meteorite with which 
the earth collides, each particle being 
burned up and so rendered luminous by 
friction as it plows through our air. 
The great stream of millions of little 
particles stretches around the sun in 
the exact path of the bright comet of 
1862, and it is highly probable that the 
stream is merely the remains of the 
comet which has been stretched out 
along its orbit by the tidal action of the 
sun. 
The particles of this stream are very 
much scattered ; it is even possible that 
a very numerous shower of small me- 
teoric stone which fell to the ground 
on July 19, 1912, were a part of the Per- 
seid swarm, though from the absence of 
reliable observations upon the direction 
from which the stones of this shower 
came this is by no means certain. 
5{C 5}C 5fS 
Meteor Crater in Arizona. 
There is at least one place on the 
earth where there is definite evidence 
that a great projectile, or more proba- 
bly a compact swarm of meteoric stones 
struck us at one time with a very high 
velocity. This remarkable structure is 
known as “Meteor Crater.” It is in 
Northwestern Arizona, about ten miles 
from the Canyon Diablo station. Here 
there is a great, round hole in the earth 
about four thousand feet in diameter, 
and the depth of which from the rim 
to the nearly level floor is about five 
hundred and seventy feet. 
When this great depression was 
made the terrific force of the collision 
pulverized, and even melted, many tons 
of rock and also threw fragments to 
great distances. It also raised the rim 
around the hole, named by early ex- 
plorers “Coon Mountain” or “Coon 
P)Utte.” The whole region for many 
miles in every direction has now been 
very carefully surveyed and explored, 
and deep drillings have been made in 
the floor of the crater, partly in the 
hope of finding the great iron mass of 
the original meteorite itself. To date 
the latter search has, however, been 
unsuccessful. 
The ejected material varies from very 
finely pulverized stone, “which seems 
to have welled out of the crater like 
flour out of a barrel,” to great masses 
weighing four thousand tons and more. 
Pieces weighing from fifty to several 
hundred pounds were thrown a dis- 
tance of two miles away, but the largest 
fragments are found, as might have 
been expected, nearer the crater rim. 
The total weight of the rock ejected 
from the crater has been estimated as 
two hundred million tons, but this esti- 
mate is probably too low. There can 
be no doubt that enormous quantities 
of the rock flour were blown to great 
distances by the wind when the col- 
lision took place. 
Scattered over the plains to a dis- 
tance of six and a half miles from the 
crater there are also found great num- 
bers of iron meteorites, apparently out- 
riding members of the great swarm 
which hit the earth. It is believed 
that, when the compact, central cloud 
reached us, a cushion of hot air was 
pushed almost as a solid mass before 
it. and that this cushion was mainly 
effective in making the crater. The tre- 
mendous outrush of air around the 
edges of the crater after the actual col- 
METEOR CRATER IN NORTHWESTERN ARIZONA. 
