American Meteorites and the National Collection 
By Epwarp P. HENDERSON, Associate Curator of Mineralogy and Petrology, U. S. 
National Museum 
[With 6 plates] 
Nearly everyone has seen “shooting 
stars” or meteors and has been im- 
pressed by the display. They appear 
without warning and are best seen at 
night. They do enter the earth’s at- 
mosphere during the daytime but are 
less likely to be seen then because the 
bright sky makes a poor background 
for the trails of glowing particles fol- 
lowing the meteor and because the low- 
hanging clouds, frequently abundant 
during the day, obscure the view. 
These ‘“‘falling stars,” which vary in 
size from small dust particles to bodies 
weighing many tons, are usually so 
high above the earth that they make 
only a silent display of fireworks; but 
now and then one penetrates the lower 
atmosphere far enough to give out a 
strange roaring sound audible over a 
very wide area. The average observer 
of such a display usually errs in esti- 
mating the distance of the falling meteor 
from him. When no sound effects are 
heard within a short interval of time, 
he may be assured that the falling ob- 
ject was a long way off. 
Particles are torn from this rapidly 
moving object and are sent whirling 
in its wake. By day only a streak of 
gray smoke resembling a cloud is vis- 
ible, but at night a luminous trail may 
be seen. These trails look small and 
unimportant compared with our low- 
hanging cumulus clouds, but their ap- 
parent size is deceptive. Floating 30 
to 40 miles above the earth, they are, 
in fact, very large, containing vast 
quantities of finely divided meteoric 
particles. This dust from “shooting 
stars” settles unnoticed upon the earth. 
The display of falling meteors can 
best be seen during certain seasons of 
the year. There are two well-known 
streams of meteors, Perseids and 
Leonids, which have furnished splen- 
did shows on various occasions during 
the past century. The Perseids are 
visible in August, usually between the 
tenth and the twentieth of the month. 
Their display is remarkably constant 
in number of meteors seen per hour, 
and also in the recurrence of the event 
year after year. The Leonids make 
their appearance less faithfully, but 
their showers have furnished the most 
spectacular displays. The phenom- 
enal Leonid shower of 1833 is still 
frequently referred to. The Leonids 
are visible toward the end of October 
and during the first few days in 
November. 
Meteors are defined as small astro- 
nomical bodies that flash across the 
sky. When these masses reach the 
earth from outer space, they are called 
meteorites. It is calculated that mil- 
lions of meteors enter our atmosphere 
each day, but records made of observed 
falls over the past 100 years show that 
a very limited number fall to the 
earth and are found. Since these 
meteors enter the earth’s atmosphere 
from all directions as the earth rotates 
on its axis, every land area has a 
chance of being struck. 
Some meteorites are large and are 
capable of doing considerable damage 
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