The National Geographic Magazine, Volume 92National Geographic Society, 1947 - Geography Indexes kept up to date with supplements. |
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Page 399
... earth is the master clock by which all other clocks are set . It is accurate to within one part in 30 million . This nightly task of timing the earth's rota- tion is carried out at the U. S. Naval Observa- tory , official keeper of the ...
... earth is the master clock by which all other clocks are set . It is accurate to within one part in 30 million . This nightly task of timing the earth's rota- tion is carried out at the U. S. Naval Observa- tory , official keeper of the ...
Page 401
... Earth Slowing Down But absolutely accurate time is a hard thing to achieve , for Mother Earth herself is not a perfect timekeeper . Though the time of the earth's rotation is the basis for our time , even that varies slightly . Records ...
... Earth Slowing Down But absolutely accurate time is a hard thing to achieve , for Mother Earth herself is not a perfect timekeeper . Though the time of the earth's rotation is the basis for our time , even that varies slightly . Records ...
Page 413
... earth . The world was divided into 24 time zones , each approximately 15 de- grees , or 1 / 24th of a circle in ... earth turns from west to east , and as we travel along with it we come toward the sun in the morning , pass under ...
... earth . The world was divided into 24 time zones , each approximately 15 de- grees , or 1 / 24th of a circle in ... earth turns from west to east , and as we travel along with it we come toward the sun in the morning , pass under ...
Contents
Adventures with the Survey Navy By Irving Johnson 131 | vi |
Erosion Trojan Horse of Greece By F G Renner 793 | xix |
Louisiana Trades with the World By Frederick Simpich With 21 illustrations in color | xxxvi |
Copyright | |
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