Range of Meteorological and Magnetic Phenomena. 61 



indicate a maximum where, in good faith, such a thing is not to 

 be discovered. This is quite true. I call attention to the 

 lines 6, 13, 14, 15. There is certainly no, or hardly an, 

 apparent maximum in the temperature-line there. But if we 

 look for a moment at this larger collection of temperature- 

 curves*, of which it is not possible to give such a large diagram, 

 it will at once be seen that for the three last of these numbers 

 the curves for the whole of the United Kingdom show a small 

 but decided maximum in all these cases. For 13 this also 

 appears in some curves for southern stations, such as Mont- 

 pellier. On the other hand, at 6 the maximum which the 

 curve for the Helder does not show is most distinctly shown 

 by the curves of the stations to the south and east of the 

 Netherlands. 



There is, I think, a most valuable use of the method here 

 explained. For one phenomenon any of the maxima may be 

 less apparent than for another. It may even be not at all so, 

 (It would seem as if magnetism were a more sensitive organ 

 than meteorology.) But as soon as some of the curves show 

 a certain maximum, there is some presumption that the others 

 ought to do so, even if they do not. In other words, that 

 there is at that particular moment an influence at work which 

 would manifest itself by creating a maximum in those curves 

 also, if only our series of observations were long enough or the 

 methods of observation sensitive enough. If at some moment 

 of the year the vertical intensity or the rainfall show a 

 maximum or minimum, even an unimportant one, the tem- 

 perature and declination must show it too — it may be smaller 

 or larger, or somewhat larger or later, but it must be there. 

 And should it decidedly not be there, depend upon it that here 

 is something worth investigating. 



But again the point now under discussion gives us a 

 valuable clue to the direction in which we must look for the 

 origin of the anomalies of our curves ; and this may lead 

 perhaps in some cases to a guess as to their causes. From 

 what has just been said it is of course very probable that the 

 maxima in 14 and 15 are due to the influence of some cause 

 which has its seat to the north or northwest of the Netherlands, 

 the one in 13 to one in the southwest, but that in to an 

 influence coining from the southeast. 



I must here refer again to a very remarkable minimum 

 occurring in some curves on or about the 1st of July, which 

 has been mentioned in the Toronto paper f. The mass of 

 material which has since come into my possession has shown 



* These diagrams also are not reproduced, 

 t Phil. Mag\ May 1898, p. 405. 



