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Page:Popular Science Monthly Volume 65.djvu/101

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THE

POPULAR SCIENCE

MONTHLY

 

JUNE, 1904.




THE TOTAL SOLAR ECLIPSE OF AUGUST 30, 1905.
By Professor W. W. CAMPBELL,

DIRECTOR OF THE LICK OBSERVATORY, UNIVERSITY OF CALIFORNIA.

THE last total eclipse of the sun observed was that of May 17, 1901, whose path crossed the islands of Mauritius, Sumatra, Borneo and New Guinea. Its durations, in Sumatra six and a half minutes, was the greatest of any observable eclipse of the last half century. The shadow touched the islands at very few accessible points, and the choice of observing stations was unusually limited. Nevertheless, observations were undertaken by a relatively large number of well-equipped expeditions from this country and Europe. At nearly all stations clouds of various degrees of thickness covered the eclipsed sun, and the work was seriously hampered by them. Fortunately, many valuable photographs were secured through thin clouds. For example, Professor Perrine, in charge of the William H. Crocker Expedition from the Lick Observatory, obtained results of great value with each of his ten instruments, though only five to twenty-five per cent, of the light passed through the clouds. In fact, it would be difficult to say wherein they could have been better, except that the intra-mercurial planet search was incomplete in one third of the area called for in the program.

A total eclipse, of short duration, occurred on September 20, 1903, in the southern Indian Ocean. The shadow did not pass over land, unless within the closed south polar continent, and no effort was made to secure observations.

A long eclipse will occur on September 9, 1904. It, too, will come and go practically unobserved, for its path passes eastward over the central Pacific Ocean without touching any known islands, and terminates on the coast of northern Chile about six minutes before sunset.