A new manual of the elements of astronomy, descriptive and mathematical .. (1868)
Kiddle, Henry, 1824-1891 · New York, Ivison, Phinney, Blakeman & co.; Chicago, S.C. Griggs & co. · leaf 111
ears of continued observations, M. Schwabe, a Germanastronomer, discovered that there was a periodical increase and de-crease of the number and size of the spots ; and Prof. Wolf, of Zurich,by comparing the observations made during the last hundred years,has shown that this period has varied… … SUN-SPOT, JTTLT 29, 1860, STTOWING THE WILLOW-n^P STETTCTtTBE. 6. The spots are mostly confined to two zones parallel to the equator,and extending from 5° to 35° from it; and they appear to have a tend-ency to arrange themselves in lines parallel to the equator. c. The duration of single spots is…
Astronomy
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