Smithsonian Institution · Washington : Smithsonian Institution · leaf 118
SOLAR DIURNAL VARIATION (C). Sorar-DrurnaL Variation or THE MaGnetic Dip OcToBER TO Makrcu, 1841—1845. (Expressed in minutes.) cal oe a er ie lee lanl eae an] F = s +0./8 … =< 126 3 | A | oa °o i ! { ! l i a Qn 2 4 6 8 10 8 14 16 18 20 22 245 3 A a Philadelphia mean time.
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