137 



IVom a comparison of various observations of the red prominences 

 seen at the eclipse of the 28th July 1851, that those objects were 

 not mere optical phenomena, but that they actually existed in the sun. 



The object of the present communication is to offer some conjec- 

 tures regarding the nature of the red prominences, and their pos- 

 sible connection with other solar phenomena. 



The comparatively faint light reflected by the prominences, their 

 overhanging forms, and the appearance at the late eclipse, of a 

 prominence completely detached from the moon's limb, all conspire 

 to prove that they are cloudy masses floating in the sun's atmo- 

 sphere ; while the existence of a long range of red prominences, 

 which, at certain stations, was seen extending over nearly a third part 

 of the moon's hmb, together with their tolerably uniform distribution 

 all round the rest of the moon's edge, prove that the matter com- 

 posing them is very copiously diffused through the sun's atmosphere. 



To account for the existence of the red prominences, the author 

 supposes that the sun's luminous atmosphere is surrounded by an 

 e7ivelope of cloudy matter, capable of absorbing part of his light, 

 and reflecting chiefly the red rays of the spectrum — ^a conjecture 

 which is founded both on the observed general distribution of the 

 red prominences, and on the appearance of a band of red light 

 just before the end of the total phase of the eclipse, which was 

 seen extending round the moon's limb, about the point where the 

 sun emerged. The serrated outline of the long range of prominences 

 indicates that the surface of the stratum of cloud is exceedingly un- 

 even, and its higher portions seen beyond the edge of the moon, 

 may constitute red prominences. It is also however supposed, that 

 just as the spots on the sun have been conceived to arise from upward 

 currents in the solar atmosphere, removing portions of its luminous 

 stratum ; the same, or similar currents, may penetrate the superin- 

 cumbent stratum of cloud, carry upwards the edges of the aperture it 

 has formed, and detach masses of cloud, so as to form higher and 

 more remarkable prominences, like the more striking objects of that 

 kind which were seen at the late eclipse. 



The author conceives that this view regarding the nature of the 

 red prominences, may also serve to explain other solar phenomena. 



1. Tlie darkness of the sun's edge, compared with his centre, is 

 generally attributed to the absorbent action of the solar atmosphere 

 on light ; but unless the thickness of the absorbent atmosphere be 



VOL. III. L 



