Science: Tin Can Party

Astronomers are as proud of the number of total solar eclipses they have witnessed as railroad conductors are of the gold service stripes on their sleeves. Dr. Samuel Alfred Mitchell, director of the Leander McCormick Observatory, University of Virginia, who has been looking at the skies for 32 years, has the great totality total of 15 min. (six eclipses) to his credit. He has had to travel 90,000 mi. to do it. Had he attended every instance of the sun’s darkening since 1900 he would have a grand total of 68.1 min. and might have traveled as far as the eclipse-causing moon (238,857 mi.) and back again. It was with much satisfaction that he radioed to Science Service in Washington that, as director of the U. S. expedition to witness last week’s solar eclipse at Niuafou Island (8,000 mi. from Washington) he had added 93.9 sec. more to his totality total.

Dr. Mitchell was satisfied but not enthusiastic with what he had seen when the moon’s shadow fell upon Niuafou. He reported that the performance was only what he expected. When, however, his 112 photographs of the phenomenon were developed, Dr. Mitchell pronounced the expedition’s success “unequaled in astronomical annals.” Spectroscopic analyses of the incandescent gases which surround the sun showed a new wavelength which scientists had never known before. The visible spectrum ranges from 8,000 to 4,000 angstrom units.* Dr. Mitchell’s wavelength was 6,770 angstrom units. The camera recorded what the astronomer’s eyes had missed—disturbances in the corona on the east and west edges of the sun, caused probably by violent motions in the inner corona. Evidences of these upheavals were seen shooting out 100,000 mi. beyond the surface of the sun. Photographs showed coronal streamers with unusual strawberry-colored domes. From careful time computations, astronomers discovered that the eclipse had begun 2 sec. before it was scheduled, ended 1 sec. early.

Two months ago, the Mitchell expedition, under the auspices of the U. S. Naval Observatory, set out to keep its 93-sec. engagement. The totality band of this year’s eclipse spread across the southern Pacific from Australia to the tip of South America. On its way it crossed only two tiny points of land: Nurakita, an inaccessible island, and Niuafou in the Tonga group, home of 1,500 Polynesian natives. Because it stands so proudly high in a treacherous sea, ships can not approach Niuafou. Mail is sent to shore in tin cans. Hence the island is familiarly called Tin Can Island. Astronomers had no choice. To see the eclipse they had to dare a difficult landing, pack themselves and their apparatus upon the inhabitable two square miles of Niuafou with the Polynesians. For baggage they carried materials for one 65-ft. and one 63-ft. camera, numerous smaller cameras, food for two months, spectroscopes, lumber, notebooks. Setting up their apparatus they tested it for a month in advance, rehearsed their parts. Rain and mist for 93 sec. at the time of the eclipse would have ruined everything.

With Dr. Mitchell were Commander Chester H. J. Keppler, administrative head of the party; Professor Ross W. Marriott, Swarthmore College; Dr. Weld Arnold, American Geographical Society. Dr. Thomas Augustus Jaggar, famed volcanologist of Hawaii, traveled with them to look at Niuafou’s volcanic formation. New Zealand also sent an expedition. Standing near the scientists at the time of the earth’s darkening, startled as much by their shining metal contraptions as by the eclipse, was the dusky, dandy High Chief of Niuafou. After everything was over, he and his bewildered subjects danced and feasted—but not on Prof. Mitchell & friends.

*One angstrom unit is equal to .000,000,0001 meter.