DISCOVERIES FROM SOLAR ECLIPSE EXPEDITIONS ' 



By S. A. Mitchell 

 Director, Leander McCormick Observatory, University of Virginia 



[With 9 plates] 



Throughout all ages of the world's history, the commg of a total 

 eclipse of the sun has always been regarded with fascinating interest. 

 Even today in some less civilized portions of the globe, a dragon is 

 believed to be devouring the sun, with the result that the monster 

 must be scared away by the beating of torn toms or must be appeased 

 by the making of sacrificial offerings. The present-day appeal to 

 intelligent people is a twofold one: first and foremost, on account of 

 the spectacular character of the phenomenon, the coming of darkness 

 during the daytime, and the matclilcss beauty of the corona, and 

 second, on account of the apparently uncanny sldll with which the 

 astronomer is able to predict hundreds of years in advance the exact 

 hour and minute when the darkening will take place and the location 

 on the earth's surface where the phenomenon may be observed. 



The modern scientific method of investigation, that of experimenta- 

 tion, came into vogue about the time of the 1842 total eclipse which 

 was greeted at Milan with shouts of "Long live the astronomers," who 

 bad provided so beautiful a phenomenon to please and interest the 

 populace. The unexpected beauty of color and form of the promi- 

 nences and the corona, coupled with the discovery of Baily beads, and 

 in the year following the discovery of the periodicity of sunspots, caused 

 an unprecedented increase in interest in the physical constitution of 

 the sun. If one of our present-day enthusiastic eclipse astronomers 

 had been alive at that time and with long life and unimpaired vigor 

 had been permitted to take part in each eclipse expedition from that 

 day to tliis, and if he had had to take his average run of luck with the 

 weather, he would have been permitted 1 precious hour of 60 golden 

 minutes to secure aU of his observational material. Among aU the 

 wonders of modern science, it is safe to state that the eclipse astron- 

 omer eclipses the performances of any other scientist in the wealth of 

 information gleaned per hour spent in securing the observations. 



' The sixth Arthur Lecture, under the auspices of the Smithsonian Institution, February 9, 1937. The 

 author observed his tenth solar eclipse as the scientifle leader of the National Geographic Society— U. S. 

 Navy expedition to Canton Island. Through the kind permission of the National Geographic Society 

 we are enabled to publish photographs from this latest eclipse, that of Juno 8, 1937.— Editor. 



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