50, 100 & 150 Years Ago: Observing Earth, Diverting Water and Girdling the World

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SEPTEMBER 1955
GEOPHYSICAL EARTH--"The historic decision of U.S. scientists to attempt to launch an artificial moon within the next three years is a symbol of man's increasing ability to view the earth as a whole. This ability is also expressed in plans for an International Geophysical Year, for 1957. The frontispiece of this issue shows a man holding a Polynesian navigation map representing a region around the Marshall Islands. Behind the map is a globe devised in about 145 B.C. by Crates of Mallus of the Stoic school. The globe divides the earth into four quarters separated by oceans. It thus poetically anticipates the discovery of North and South America and Australia."

TRUE NORTH--"In the past few years it has become possible to read the magnetic record for millions of years by means of certain natural compass needles which nature has frozen into the rocks. Reading these magnets in rocks at various places around the world, we find evidence of astounding changes in the earth's main axial field. During the Tertiary period (between 60 million and one million years ago) the north and south geomagnetic poles reversed places several times! --S. Keith Runcorn"

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