188 - Researches on Solar Physics. 
24, Let us now endeavor to answer the second question—“ Is 
the photosphere of our luminary to be viewed as composed of 
heavy liquid or solid matter, or is it of the nature of a cloud?” 
One characteristic of the sun’s surface is the appearance (espe- 
cially in connexion with spots) of faculee, or patches of a bright- 
ness greater than that of the photosphere immediately around 
them, this difference in brightness being much more conspicuous 
near the limb than near the center. One explanation of these 
ie ag would be, that the luminous matter of the sun has 
around it. On the other hand, very little will be gained when 
the matter is thrown up near the visual center, where we may 
of our luminary, are more of the nature of a cloud. A clout 
has been defined by Sir J. Herschel to consist of solid or liquid 
matter, formed from the condensation of a vapor not floating 10 
gequilibrio, but sinking in i of less specific 
} , bu ig in a gaseous medium 
gravity than itself—sinking, however, with extreme slowness, 
