VOL. LXXXV.] PHILOSOPHICAL TRANSACTIONS. 4S3 



How very ill would this observation agree with the ideas of solid bodies bob- 

 bing up and down in a fiery liquid? with the smoke of volcanos, or scum on 

 an ocean? And how easily it is explained on the foregoing theory. The removal 

 of the shining atmosphere, which permits us to see the sun, must naturally be 

 attended with a gradual diminution on its borders; an instance of a similar kind 

 we have daily before us, when through the opening of a cloud we see the sky, 

 which generally is attended by a surrounding haziness of some short extent; and 

 seldom transits, from a perfect clearness, at once to the greatest obscurity. 



Aug. 26, 1792, I examined the sun with several powers, from 90 to 500. It 

 appeared evidently that the black spots are the opaque ground, or body of the 

 sun; and that the luminous part is an atmosphere, which, being interrupted or 

 broken, gives us a transient glimpse of the sun itself The 7-feet reflector, 

 which was in high perfection, represented the spots, as it always used to do, 

 much depressed below the surface of the luminous part. Sept, 2, 1792, I saw 

 2 spots in the sun with the naked eye. In the telescope I found they were 

 clusters of spots, with many scattered ones besides. Every one of them was 

 certainly below the surface of the luminous disc. Sept. 8, 1792, having made 

 a small speculum, merely brought to a perfect figure on hones, without polish, 

 I found, that by stifling a great part of the solar rays, the object speculum would 

 bear a greater aperture; and thus enabled me to see with more comfort, and less 

 danger. The surface of the sun was unequal; many parts of it being elevated, 

 and others depressed. This is here to be understood of the shining surface only, 

 as the real body of the sun can probably be seldom seen, otherwise than in its 

 black spots. It may not be impossible, as light is a transparent fluid, that the 

 sun's real surface also may now and then be perceived ; as we see the shape of 

 the wick of a candle through its flame, or the contents of a furnace in the 

 midst of the brightest glare of it; but this I should suppose will only happen 

 where the lucid matter of the sun is not very accumulated. 



Sept. 9, 1792, I found one of the dark spots in the sun drawn pretty near 

 the preceding edge. In its neighbourhood I saw a great number of elevated 

 bright places, making various figures: I shall call them faculas, with Hevelius; 

 but without assigning to this term any other meaning than what it will hereafter 

 appear ought to be given to it. I saw these faculae extended, on the preceding 

 side, over about -^ part of the sun; but so far from resembling torches, they ap- 

 peared like the shrivelled elevations on a dried apple, extended in length, and 

 most of them joined together, making waves, or waving lines. By some good 

 views in the afternoon, I found that the rest of the surface of the sun does not 

 contain any faculae, except a few on the following, and equatorial part of the 

 sun. Towards the north and south I saw no faculae; there was all over the sun 

 a great unevenness in the surface, which had the appearance of a mixture of 



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