SUNSPOTS AND WEATHER. 505 



SUNSPOTS AND WEATHER. 



By Professor ERNEST W. BROWN, 



HAVERFORD COLLEGE. 





IT is perhaps not far from the truth to say that the most pressing 

 problem, as far as the daily needs of humanity are concerned, 

 consists in finding some method of predicting the weather. Of the 

 great value which a solution would have it is not necessary to say a 

 word. Yet, in spite of many attempts, the chief problem is as yet 

 unsolved. One may go a step further and say that there is at present 

 no indication of any approach to a solution in the work which has 

 hitherto been published. It is possible to forecast the weather with 

 fair accuracy for a day or two in advance, but the methods by which 

 this is done do not appear to have any bearing on the problem of pre- 

 dicting what the weather will be next week, next month or next year. 

 The latter question must be approached in a quite different manner, 

 and it is the object of this article to show the degree of success attained 

 by one attempt to disentangle the wider fluctuations of climate which 

 nearly every region of the earth's surface shows from year to year. 



Weather and climate, like all other phenomena of nature, are nothing 

 more than particular cases of the interaction of certain laws. Properly 

 speaking, chance plays no part in their variations. That the motions 

 of the atmosphere can be classed under well-known mechanical prin- 

 ciples, there can be little doubt ; that the various types of weather and 

 climate are capable of being deduced from those principles with a 

 sufficiently powerful method of analysis is equally certain; but whether 

 such a method has yet been invented or is in process of being discovered 

 at the present time is open to doubt, if we may judge from the very 

 little that has hitherto been done in the direction of deducing the 

 observed phenomena from the laws which govern them. The difficul- 

 ties presented by this natural and logical process have caused meteor- 

 ologists to turn to some other method of restoring order out of the 

 chaos. Instead of deducing the phenomena from the general laws, at- 

 tempts are being made to bridge the chasm which separates them by 

 starting with the observations and trying to find out if some kind of 

 order can be discovered — a support on which it may be possible to 

 continue the bridge towards the opposite bank. 



The procedure to be adopted when the latter method is used is 

 sufficiently simple. Large numbers of observations of temperature, 



VOL. LXVI. — 33. 



