L62 Mr. J. N. Lockyer on Recent 



we have. Taking the old view of the elements, we have fire re- 

 presented by our sun, variable if our sun is variable. Earth, air, 

 and water, in this planet of ours we must recognize as constants. 

 From this point of view, therefore, it is not at all to be won- 

 dered at that both magneticians and meteorologists should 

 have already traced home to solar changes a great many of 

 the changes with which we are more familiar. This second 

 branch of work depends obviously upon the work done in the 

 first, which has to do with the number (the increasing or de- 

 creasing number) of the spots and prominences, and the vari- 

 ations of the positions which these phenomena occupy on the 

 surface of the sun. As a result of this work, then, we shall 

 have a complete cataloguing of every thing on the sun, and a 

 complete comparison of every thing on the sun with eveiy me- 

 teorological phenomenon which is changeable in our planet. 



When we come to the third branch of the work, the newest 

 branch, things are not in such a good condition. The workers 

 are too few ; and one of the objects of any one who is inter- 

 ested in this kind of knowledge at the present moment must 

 be to see if he cannot induce other workers to come into the 

 field. The attempt to investigate the chemistry of the sun, even 

 independently of the physical problems which are, and indeed 

 must be, connected with chemical questions, is an attempt 

 almost to do the impossible unless a very considerable amount 

 of time and a very considerable number of men be engaged 

 upon the work. If we can get as many workers taking up 

 various questions dealing with the chemistry of the sun as 

 we find already in other branches, I think we may be certain 

 that the future advance of our knowledge of the sun will be 

 associated with a future advance of very many problems which 

 at the present moment seem absolutely disconnected from it. 



I have today to limit myself to this chemical branch of the 

 inquiry ; and first let me begin by referring to the characteris- 

 tics of the more recent work with which I have to deal. Here, 

 as in other branches of physical and chemical inquiry, advance 

 depends largely upon the improved methods which all branches 

 of the science are now placing at the disposal of all others. 

 Our knowledge of the chemical nature of the sun is now being 

 as much advanced by photography, for instance, as that de- 

 scriptive work of which I spoke in the first instance (which 

 deals with the chronicling and location of the various phe- 

 nomena) has, in its turn, been advanced by the aid of photo- 

 graphy. I do not know whether the magnificent results 

 recently obtained by Dr. Janssen have been brought before 

 this Society ; but the increase in photographic power recently 

 secured by Dr. Janssen is one which was absolutely undreamt 



