NOTES BY THE EDITOR. XV 



and using a red glass to diminish the glare of the light, admitted 

 by the slit, the prominence being seen by means of the C liiie in 

 the red. Mr. Lockyer had a design for seeing the prominences as 

 a whole by giving the slit a rapid motion of small extent, but this 

 proved to be superfluous, and they are now habitually seen with 

 their actual forms. Nor is our power of observing them restricted 

 to those which are so situated that they are seen by projection 

 outside the sun's limb ; such is the power of the spectroscopic 

 method of observation, that it has enabled Mr. Lockyer and 

 others to observe them right on the disc of the sun, — an important 

 step for connecting them with other solar phenomena. One of 

 the most striking results of the habitual study of these promi- 

 nences is the evidence they afford of the stupendous changes 

 which are going on in the central body of our system. 

 Prominences, the heights of which are to be measured by thou- 

 sands and tens of thousands of miles, appear and disappear in the 

 course of some minutes. And a study of certain minute changes 

 of position in the bright line F, which receive a simple and 

 natural explanation by referring them to proper motion in the 

 glowing gas by which that line is produced, and which we see no 

 other way of accounting for, have led Mr. Lockyer to conclude 

 that the gas in question is sometimes travelling with velocities 

 comparable with that of the earth in its orbit. Moreover, these 

 exhibitions of intense action are frequently found to be intimately 

 connected with the spots, and can hardly fail to throw light on the 

 disputed question of their formation. Nor are chemical composi- 

 tion and proper motion the only physical conditions of the gas 

 which are accessible to spectral analysis. By comparing the 

 breadth of the bright bands (for though narrow they are not 

 mere lines) seen in the prominences, with those observed in the 

 spectrum of hydrogen, rendered incandescent under different 

 physical conditions. Dr. Frankland and Mr. Lockyer have deduced 

 conclusions respecting the pressure to which the gas is subject in 

 the neighborhood of the sun." 



Since the discovery of Lockyer's, Janssen's, and Huggins' 

 method of viewing the prominences, Zollner has discovered a way 

 of seeing them as a whole. His method will be found on page 322 ; 

 Prof. Young's method will be also found in detail on page 315. 

 He makes use also of the Cline, and likens it to looking at the sun- 

 set sky through a chink in the window. It is thought that this 

 method may be used to advantage in the coming transit of Venus. 

 The total eclipse of August 7th, 1869, was very fully observed. 



