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phenomena from which he derives his inferences concerning the na- 

 ture of the sun, Dr. Herschel proceeds next to treat of the regions of 

 solar clouds. The point he here principally insists upon, is, that the 

 above-mentioned appearances are wholly incompatible with the hy- 

 pothesis of the shining matter of the sun being a liquid, or an elastic 

 fluid of an atmospheric nature ; since, by the laws of hydrostatics, 

 all the depressions would be instantly filled up, and the elevations 

 would as rapidly subside. - The opinion he advances is, that this 

 shining matter exists in the manner of empyreal, luminous, or phos- 

 phoric clouds, residing in the higher regions of the solar atmosphere. 

 Of these he assumes two different regions, or a double stratum of 

 clouds, whereof the lower, viz. that which is nearest the sun, consists 

 of clouds less bright than those of the upper stratum. The lower 

 clouds are also more closely connected, while the upper ones are 

 chiefly detached from each other, and permit us everywhere to see 

 through them. 



A number of additional observations are here added ; from which 

 it is inferred, that the inferior clouds are opake, and probably not 

 unlike those of our planet ; and that their light is only the uniform 

 reflection of the surrounding superior, self-luminous region. These 

 lower clouds, it is thought, compose what the Doctor calls flats; and 

 by a contrivance here described, he demonstrates, that the quantity 

 of reflected light they transmit to us is to that of the superior and 

 self-luminous clouds in the proportion of 469 to 1000. 



By the same process he proves also that, adhering to the same 

 proportion, the quantity of light reflected by the solid body of the 

 sun at the openings is represented by a number no greater than seven. 

 Speaking of the planetary clouds, it is shown of what eminent service 

 they must be to the whole solar system ; since, by their means, nearly 

 one half more light is transmitted to us from the sun than we should 

 receive from the self-luminous stratum alone. 



In a section on the solar atmosphere, after showing that its exist- 

 ence cannot be denied, since the clouds could not be kept suspended 

 in the manner in which they are without an elastic atmospherical 

 fluid to bear them up, reasons are assigned why this atmosphere 

 must be of a greater extent, of considerable density, transparent, and, 

 like ours, subject to agitations by winds and other disturbing causes. 

 From these various observations and inferences is next derived a 

 theoretical explanation of the solar phenomena ; wherein the manner 

 is described in which all the above-mentioned appearances on the 

 surface of the sun are likely to be generated : after which follows 

 an enumeration of the signs from which we may infer a deficiency or 

 abundance of luminous matter in the sun. The former of these are a 

 deficiency of empyreal clouds, of openings, and of ridges, nodules, 

 and all that may be considered as prominences ; whereas the oppo- 

 site appearances are indications of increasing light and heat. The 

 Doctor now does not scruple to assert that openings with great flats, 

 ridges, nodules, and crankles, may induce us to expect a copious 

 emission of heat, and therefore mild seasons ; and that, on the con- 

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