Range of Meteorological and Magnetic Phenomena. 65 



longer series. But I fully expect that when this is quite 

 computed these doubts will be cleared away. 



There is, however, another class of doubts which must 

 perhaps be allowed as yet to stand over. It will be seen that 

 between the maxima marked 15 and 16 I suggest for the 

 upper curves two minima and an unimportant maximum 

 between them, while lower down I have only been able to 

 trace a single minimum. This may of course be consistent 

 with the facts. Eventually for one phenomenon a certain 

 maximum may become so slight that it can no longer be 

 detected, at least not by our present methods ; and thus the 

 two minima before and after it may merge into one, although 

 other phenomena show two minima. 



Another fact of the same nature occurs perhaps between the 

 July and August maxima, between the vertical lines 9 and 10. 

 The dotted line between these two is much more crooked than 

 the lines 9 and 10 seem to warrant. On the other hand, 

 nearly all the lines show very slight indications that this 

 minimum is indeed a double one separated by a very slight 

 maximum. But this feature is so faint that I did not feel jus- 

 tified for the present in drawing the vertical lines accordingly. 

 Again the line 17 is a doubtful one. Of course this is 

 partly only a technical difficulty. Where the curves are so 

 near together as in this part of the diagram, the vertical lines 

 must seem — not really be — -more crooked than they are in the 

 summer part of the diagram, where they expand to such a 

 length. Still I have a feeling that line 17 is also in reality 

 composed of two maxima, of which one, in December, ought 

 to have the number 17, and another, chiefly in January, the 

 new number 18. 



I might of course multiply instances like these, but I feel 

 that this is at present useless. The seventeen lines which I 

 have numbered will, I think, be found in future to be a near 

 approximation to truth for Western Europe so far as the most 

 remarkable features go. But numberless other subsidiary 

 vertical lines may eventually be filled in in course of time 

 when more and better material shall be at hand than I could 

 avail myself of as yet. 



But this, I think, is the result of this part of the work : 

 There is one potent cause which for a large part rules all 

 meteorological and magnetic phenomena, and influences them 

 all in a similar way nearly simultaneously. 



1 do not of course pretend to teach a new doctrine in these 

 words, but I think I have shown a new proof of it. And 

 also how largely the simple method which 1 have used may in 

 future contribute to the solution of meteorological problems. 

 Phil. Mag. S. 5. Vol. 47. No. 284. Jan. 1899. F 



