A popular handbook and atlas of astronomy, designed as a complete guide to a knowledge of the heavenly bodies and as an aid to those possessing telescopes (1891)
Peck, William, Sir, 1862-1925 · New York, G. P. Putnam's Sons · leaf 76
ted in two zones on the solar surface about twenty degrees in breadth, lyingon either side of the equator. It is found, too, that the number of spots is not always, even approximately,the same. At times, no spots can be seen on any part of the surface, while at other times largenumbers are visible.… … THE SUN. the variation of solar activity, is, strangely enough, in some way connected with the variation of the magneticneedle, for when the suns activity is at a maximum, the diurnal movement of the compass is then greatest. At first it was thought that sun-spots were simply quantities of slag or…
Astronomy
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