SUN-SPOT, STORM, AND FAMINE. 33 



daylight, and the exact mid-day elevation of the sun for every 

 day in the year, is not one whit better able to protect his 

 crops or his herds against storm or flood than the tiller of 

 the soil or the tender of flocks a hundred thousand years or 

 so ago, who knew only when seed-time and summer and 

 harvest-time and winter were at hand or in progress. 



The evidence thus afforded is by no means promising, 

 then, so far as the prediction of special storms, or floods, 

 or droughts is concerned. It would seem that if past ex- 

 perience can afford any evidence in such matters, men may 

 expect to recognize cycles of weather change long before 

 they recognize corresponding solar cycles (presuming always 

 that such cycles exist), and that they may expect to find 

 the recognition of such association utterly barren, so far as 

 the possibility of predicting definite weather changes is 

 concerned. It would seem that there is no likelihood of 

 anything better than what Sir J. Herschel said might be 

 hoped for hereafter. "A lucky hit may be made; nay, 

 some rude approach to the perception of a 'cycle of 

 seasons ' may possibly be obtainable. But no person in his 

 senses would alter his plans of conduct for six months in 

 advance in the most trifling particular on the faith of any 

 special prediction of a warm or a cold, a wet or a dry, a 

 calm or a stormy, summer or winter" far less of a great 

 storm or flood announced for any special day. 



But let us see what the cycle association between solar 

 spots and terrestrial weather actually is, or rather of what 

 nature it promises to be, for as yet the true nature of the 

 association has not been made out. 



It has been found that in a period of about eleven years 

 the sun's surface is affected by what may be described as a 

 wave of sun-spots. There is a short time a year or so 

 during which scarce any spots are seen ; they become more 

 and more numerous during the next four or five years, until 

 they attain a maximum of frequency and size ; after this they 

 wane in number and dimensions, until at length, about eleven 

 years from the time when he had before been freest from 



