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XXX.—On the Red Prominences seen during Total Eclipses of the Sun. 
Part Il. By Wiuu1am Sway, F.R.S.E. 
(Read April 19, 1852.) 
In the first part of this paper, I have endeavoured to prove, that the red pro- 
minences seen during total solar eclipses, exist in the sun; and I now propose to 
state some views which have occurred to me as to the nature of those remarkable 
objects, and their possible connexion with other solar phenomena. It is not, 
however, without great misgivings that I venture on this subject; for we know so 
little of the sun, that any hypothesis regarding the constitution of his atmosphere, 
can amount only to a conjecture, possessing more or less probability according to 
the variety of the appearances it serves to explain, and the exactness with which 
theory and observation correspond in each case: and I am well aware that views 
which may seem probable to myself may not appear equally so to others, whose 
greater experience in observing the sun constitutes them better judges of such 
questions. 
1. On the Nature of the Red Prominences, and their Mode of Distribution in the Solar 
Atmosphere. 
For the reasons stated in the first part of this paper, I shall assume that the 
red prominences exist in the sun’satmosphere. They must, then, to use the words 
of Sir Joun HerscueEt, be “ cloudy masses, of the most excessive tenuity ;’* for being 
placed so near the sun, if their density approached that of the rarest terrestrial 
clouds, they could not fail to reflect an intensely brilliant light. Now this is far 
from being the case; for although they are by no means faint objects, neither are 
they very bright ones. 
Another circumstance, which proves that the red prominences are gaseous and 
not solid bodies, is the overhanging form sometimes assumed by them, which, in 
the case of solid bodies, would result in the impending portions breaking off, and 
falling under the action of the sun’s gravitation; and the same conclusion follows 
inevitably from the appearance, at the late eclipse, of a red mass completely de- 
tached from the moon’s limb, and therefore evidently floating in the sun’s atmo- 
sphere.t 
The red prominences being thus obviously vaporous masses, | shall inquire, 
first, into the manner of their distribution in the solar atmosphere. Now the ob- 
* Herscue’s Outlines of Astronomy, par. 395. 
+ M. Araco reasons in the same manner, in the Annuaire for 1852, p. 344. 
VOL. XX. PART III. 6H 
