274 Proceedings of the Asiatic Society, [Dec. 



part ; for the outer portions of the Solar atmosphere must approxi- 

 mate rapidly to the temperature of space. 



I have on one of my Photographs what I consider to be the image 

 of this densest portion of the Solar atmosphere as an intensely 

 luminous stratum, rather more than 7,000 miles thick. From this 

 I conceive that the protuberances are formed. 



One of those seen on this occasion is remarkable for its enormous 

 height and its singular structure. It has been examined with Spectro- 

 scope and Polariscope, and we have six Photographs of it exhi- 

 biting its marvellous structure. These have enabled me to form a 

 theory of its construction as follows. From some cause, two violent 

 jets of gas issued from points on the Sun's limb 20,000 miles apart, 

 the more northern and larger of these was nearly perpendicular to 

 the surface, the southern was inclined at about 40° to that surface : 

 rushing through the luminous stratum, they carried off with them its 

 lighter constituents, and meeting about 16,000 miles above the Solar 

 surface, they joined. But the axes of these jets were not in the same 

 plane : hence arose a rotatory motion in the whole, and gas and vapour, 

 whirling in a vortex, rose to a height of 90,000 miles above the surface 

 of the Sun. That gas was Hydrogen. If other gases were there, 

 the traces were faint, and escaped my notice. The vapours of which 

 I saw traces, were Sodium and Magnesium, the two lightest. Where 

 I examined this horn in the upper part, I think I may safely say, Iron 

 was absent ; and if the gas had taken any of these with it, it had 

 dropped them as it rose. 



But this was a singular and exceptional phenomenon. Such vio- 

 lent outbursts seem uncommon even in the Sun, and, of course, the 

 formation of a rotating column such as this, would be less so. Jets 

 of gas ordinarily carry up with them portions of incandescent vapour 

 forming with them columnar protuberances, and when, as would seem 

 most common, the escape is still more gradual, bubbles of gigantic 

 size are formed in the luminous stratum which are the ordinary round- 

 ed prominences. These are but of short duration. If an air-bubble on 

 water be proverbially short-lived, how short would be the duration 

 of a bubble merely covered with vapor, were that not prevented 

 from subsiding by the constant fresh supplies of gas from below. 

 Really broken in manj^ places, the remaining clouds of vapour Avould 



