Page:Popular Science Monthly Volume 68.djvu/555

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551
AN ECLIPSE EXPEDITION TO SPAIN

AN ECLIPSE EXPEDITION TO SPAIN
By Dr. S. A. MITCHELL

COLUMBIA UNIVERSITY

IF we could sum up the total duration in minutes and seconds of recent eclipses, we should be astounded that astronomers from such phenomena have discovered so very much. Since the spectrograph and the photographic plate were first used together at an eclipse, the sun has been covered up by the moon somewhat less than twenty minutes of time, yet, in these few moments, a great wealth of information has been gained from the eclipsed spectrum. Each eclipse settles some problems, and teaches us how to attack others, and astronomers are most enthusiastic at such a time, trying new instruments and improved methods of research. More interest was shown in the 1905 eclipse than ever before, one reason for this being that the moon's shadow path fell upon a readily accessible part of the globe, and the eclipse occurred at a time of the year (August 30) when most college men were having their summer vacation. At the last eclipse, in 1901, American astronomers had to travel as far away from home as possible, in that a trip half way round the world was taken; and when one considers the number of instruments, and the great amount of freight that the modern astronomer has to carry with him, the task is no small one.

At the eclipse of last year the moon's shadow touched the earth's surface at sunrise in Manitoba, and after crossing through Canada at cannon-ball speed, it left Labrador about 8 a. m. on its trip across the Atlantic. Shortly after noon the shadow cut into Spain, then on through the Mediterranean, northern Africa, Egypt, and left the earth's surface at sunset on the coast of the Indian Ocean.

Spain was chosen by the majority of astronomers, both because the duration of totality was longer, and because the weather conditions promised better; and here in a path one hundred and twenty miles in width running diagonally across the peninsula, hundreds of astronomers, American and European, were gathered.

The party sent out by the United States government was under the general direction of Rear-Admiral Colby M. Chester, U.S.N., superintendent of the Naval Observatory. Three men-of-war were furnished by the Navy Department for the purposes of the expedition, the U.S.S. Minneapolis, U.S.S. Dixie and U.S.S. Cæsar, the first named being the flagship of the squadron.

The three vessels left separately from the United States about the end of June, and met in Gibraltar about the middle of July. 'Gib'