. Elements of astronomy: accompanied with numerous illustrations, a colored representation of the solar, stellar, and nebular spectra, and celestial charts of the northern and the southern hemisphere. s regards spots? 120. How does the Suns surface look, where APPEAEANOES ON THE SUNS DISK. 63 of all magnitudes, from hardly-visible, softly-gleaming,narrow tracts 1,000 miles long, to continuous complicatedridges 40,000 miles and more in length, and from 1,000 to4,000 miles broad. Ridges of this kind often surround aspot, and hence appear the more conspicuous; such aridge is shown in Fig. 1, page
. Elements of astronomy: accompanied with numerous illustrations, a colored representation of the solar, stellar, and nebular spectra, and celestial charts of the northern and the southern hemisphere. s regards spots? 120. How does the Suns surface look, where APPEAEANOES ON THE SUNS DISK. 63 of all magnitudes, from hardly-visible, softly-gleaming,narrow tracts 1,000 miles long, to continuous complicatedridges 40,000 miles and more in length, and from 1,000 to4,000 miles broad. Ridges of this kind often surround aspot, and hence appear the more conspicuous; such aridge is shown in Fig. 1, page 61. Sometimes there ap-pears a very broad white platform round the spot, andfrom this white crumpled ridges pass in various 20. Other Appearances on the Suns Disk.—The wholesurface of the Sun, except those portions occupied by thespots, is coarsely mottled; and, in-deed, the mottledappearance requiresno very great opti-cal power to renderit visible. Viewedthrough a large tel-escope, the surfaceseems to be madeup principally of lu-minous masses,called by Sir Wil-liam Herschel cor-rugations, and de-scribed by other ob-servers as resem-bling rice-grains,granules, The term. Fig. 29.— Willow-leaves in a Sun-spot. A,tongue of facula stretching out into the , clouds. C, layers of willow-leaves in thepenumbra. willow-leaves has been appropriately applied to appear-ances sometimes observed in the penumbrae of consist of elongated masses of unequal brightness, ii; is not covered with spots ? Of what does it seem to be made up, when viewedthrough a large telescope? 121. What is meant by willow-leaves f 122. What is 64 THE SUN. so arranged that for the most part they point like so manyarrows to the centre of the nucleus, giving to the penum-bra a radiated appearance. At other times, and occasion-ally in the same spot, the jagged edge of the penumbraprojecting over the nucleus has caused the interior edgeof the penumbra to be likened to coarse th
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectastronomy, bookyear18
