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X. Note on the Sun's Spots. By Daniel Vaughan, Esq.* 



IN my article published in the May Number of the Philoso- 

 phical j\Iagazine, I eudeavoured to show that the heating 

 and illuminating action of suns, if maintained by the setherial 

 contents of space, can fluctuate only through the influence of 

 aarrounding worlds. But, though I off'ered an explanation of 

 the periodicity of the solar spots, I deem it advisable to point 

 out the precise manner in which they may arise from the causes 

 to which T have ascribed them, and thus to furnish a more satis- 

 factory basis for the tests of observation. 



It appears, as a legitimate deduction from my theory on solar 

 light, that the dark spots must be deficient in number, or entirely 

 absent, when the sun is advancing into the realms of more dense 

 sether; and that they must be most numerous and extensive 

 when he is departing from these localities and entering a more 

 rarefied ?ethcrial fluid. In the first case, his permanent atmo- 

 sphere, which takes no part in the emission of light, must be 

 heated most intensely in its uppermost strata, and thus broiight 

 into a state of the greatest security from disturbances. But 

 when the supply of setherial fuel from space gradually dimi- 

 nishes, and heat declines near the surface of the vast ocean of 

 incombustible gases, the elevated temperature previously trans- 

 mitted to great depths would produce the most violent commo- 

 tions of its aeriform matter. To such storms or swellings in the 

 sun's non-luminous envelope we may ascribe his spots. The 

 transparency of this gaseous appendage, together with the effects 

 of flame in intercepting the range of vision, will account for the 

 fact that the spots appear as hollows in the sunn's disc. 



If an astronomer, situated at the moon, were engaged in a 

 telescopic survey of the earth, he could distinguish volcanic erup- 

 tions from many of our most violent tornadoes only by observing 

 how the latter changed their position with respect to other ter- 

 restrial objects. It is only by a similar test that we can decide 

 whether the sun's spots are to be regarded as indications of great 

 storms in his atmosphere, or of the emission of gaseous fluids 

 from his internal regions. The evidence which observation has 

 hitherto aff'orded seems favourable to the first hypothesis. But 

 it must be extremely difficult to form any correct ideas of the 

 changes which occur beneath the sun's surface, from the effects 

 of a violent heat in volatilizing his materials, while the influence 

 of an enormous pressiu-e is exerted in maintaining them in a 

 solid or a liquid condition. 



Cincinnati, Ohio, June 25, 1858. 



* Communicated by the Autlior, 



