of the region where the eclipse is total. Since the shadow of the moon passes across the earth at the furious rate of 1300 miles an hour, a total eclipse of the sun lasts for only a few minutes,—and for this length of time, short as it is, some thanks is due to the fact that the earth, in revolving upon its axis, carries the observer and the ground upon which he stands along the same direction in which the shadow is moving._-_figure_138.jpg)
RELATIVE POSITION OF THE SUN, MOON AND EARTH AT THE TOTAL SOLAR ECLIPSE OF SEPTEMBER 10, 1923.
(The two words at the point of the shadow's contact with the Earth are "Catalina" and "San Diego.") Drawing by Dr. Mars F. Baumgardt, Curator of Clark Observatory, Los Angeles, Calif. Total eclipses are of extremely rare occurrence and only happen about once in every three hundred years for any selected spot on the earth's surface.
An interesting description of a total eclipse may be found in Flammarion's "Astronomy for Amateurs":
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