Stars and telescopes; a hand-book of popular astronomy founded on the 9th ed. of Lynn's Celestial motions (1901)
Todd, David P. (David Peck), 1855-1939, Lynn, William Thynne, 1835-1911 · Boston, Little, Brown · leaf 88
Schwabe of Dessau in 1838. The subject has sinceattracted much attention, and the period, so far asit is constant, has been pretty accurately determinedby Wolf of Zurich to be a little more than elevenyears; but the physical cause of the periodicity is notyet satisfactorily explained. A recent… … THE SUN {from a photograph by Rutherfurd)(Faculae are shown adjacent to tlie spots near the SutCs limb) Spoerer from the spots alone. The slowing down as thepoles are approached is remarkably verified, his results giving,for the rotation period at latitude 750, no less than 38d.54.M. Duners…
Astronomy
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