124 THE CANADIAN NATURALIST. [June 



these important results, and a few minutes after tlieir communica- 

 tion to M. Delaunay, of the French Academy, there was received 

 by that gentleman a letter from M. Janssen, stating that during 

 the progress of the eclipse he had conceived the possibility of 

 attaining the same end by the same means as Mr. Lockyer was at 

 that very time independently working at, and that on the 

 following day he had experimentally confirmed his idea, and drawn 

 the altered outline of one, the same protuberance he had observed 

 the day before during the eclipse. Since then these astronomers 

 and other spectroscopists — notably Father Secchi, of Rome — have 

 worked in the same field, and vastly enlarged our knowledge of 

 solar physics. I can but briefly enumerate the conclusions 

 arrived at. It is now determined, with tolerable certainty, that 

 there is a very attenuated atmosphere of burning hydrogen 

 enveloping the sun at every point, measuring, in average height, 

 about 5,000 miles; but at certain points, and chiefly near the 

 equator, upheaved by internal volcanic forces within the sun into 

 masses twenty times that height, and then wafted about by solar 

 whirlwinds. Then, from the protuberances or prominences seen 

 during an eclipse, the expulsive force is so violent that it displaces 

 not only the light hydrogen which forms the outermost layer of 

 atmosphere, but also projects from a deeper stratum the heavier 

 vapours of iron and other metals into the base of the hydrogen 

 flames. This outer layer has been called the chromosphere, from 

 its giving a spectrum of bright-coloured lines. Here and there, 

 as some of the photographs taken during the three last eclipses 

 show, and as spectroscopic observations verify, clouds of hydrogen, 

 and even of magnesium, are carried away, burning, into space, 

 quite detached from the visible solar atmosphere, though probably 

 within the limits of the real atmosphere, as certain of the 

 hydrogen lines in the spectra of the protuberance extend faintly 

 beyond the others, and indicate the extension of the atmosphere 

 far beyond its more perceptible bounds. 



Lockyer's description of a chromosphere is quite picturesque : 

 " In difierent parts the outline varies. Here, it is undulating and 

 billowy ; there, it is rugged to a degree ; flames, as it were, darting 

 out of the general surface, and forming a rugged, fleecy, inter- 

 woven outline, which, at places, is nearly even for some distances, 

 and then, like the billowy surface, becomes excessively uneven in 

 the neighbourhood of a prominence. Here one is reminded of 

 the fleecy, infinitely delicate cloud-films of an English hedgerow, 



