126 THE CANADIAN NATURALIST. [JuDC 



in which the reversion of the bright lines takes place, unless there 

 be an area of condensation, as proposed above. The interior has 

 been called the photosphere. 



Whether the chromosphere, or the chromosphere and photo- 

 sphere are alone gaseous, and the nucleus liquid, or whether there 

 are not successive rings of simple or mixed gases, of decreasing 

 density, from the centre to the circumference, will probably be 

 determined by more extended observations on the spectra of solar 

 spots. These spots, as you are aware, have been the subject of 

 much controversy, and the spectroscope has not set it at rest. It 

 is assumed by some that there is a relation between the spots, the 

 protuberances, and the fecul?e, which are generally observed in 

 the neighbourhood of the spots. When a spot is visible on the 

 edo-e of the sun's disc, a protuberance may often be detected in 

 the neighbourhood, as, for instance, in the following observation 

 by Mr. Lockyer : — 



"On the 21st April there was a spot very near the limb which 

 I was enabled to observe continuously for some time. At 7.30 

 a.m. there was a prominence visible in the field of view, in which 

 tremendous action was evidently going on, for the C. D. and F. 

 lines were magnificently bright in the ordinary spectrum itself; 

 and as the spot-spectrum was also visible, it was seen that the 

 prominence was in advance of the spot. The injection into the 

 chromosphere surpassed everything I had seen before, for there 

 was a magnesium cloud quite separated from the limb, and liigh 

 up in the prominence itself. By 8.30 the action had quieted 

 down, but at 9.30 another throb was observed, and the new 

 prominence was moving away with tremendous velocity. While 

 this was going on, the hydrogen lines suddenly became bright on 

 the other side (the earth's side) of the spot, and widened out 

 considerably — indeed, to such an extent that I attributed their 

 action to a cyclone, although, as you know, this was a doubtful 

 case. Now, what said the photograj^hic record ? The sun was 

 photographed at lOh. 55m. a.m., and I hope you will be able to 

 sec on the screen how the sun's surface was disturbed near the 

 spot. A subsequent photograph at 4h. Im. p.m. on the same 

 day shows the limb to be actually broken in that particular place 5 

 the photosphere seems to have been actually torn away behind the 

 spot, exactly when the spectroscope had afi"ordcd me possible 

 evidence of a cyclone." 



Another instance is noted by D. Curtis in his report. He 



