192 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 



data, Fritz shows that the aurora maxima occur 0.73 of a 

 year alter the sun-spot maxima, while the aurora minima oc- 

 cur 0.30 year before the spot minima. These small devia- 

 tions from absolute coincidence may, however, possibly be 

 due to the imperfections of our data; the auroral changes 

 are much more energetic than those of the sun-spot frequen- 

 cy. There is good evidence of the existence of a period of 

 5 x 11.11=55.55 years, and Fritz even suspects one of 220 or 

 222 years' duration. 



The subject of the connection between rainfall cycles and 

 sun-spot cycles has called, forth considerable correspondence, 

 much of which is noticed in JSTature, where articles have ap- 

 peared by Dr. "W. W. Hunter, Dr. E. Bonavia, C. Meldrum, 

 A. Buchan, and S. A. Hill. 



The general result of these investigations is, we think, quite 

 decidedly favorable to the conclusion that the solar spots 

 and temperatures change in parallel cycles, and affect every 

 feature in terrestrial meteorology. 



The subject can only be properly studied by including ob- 

 servations from the whole earth in an analysis, and we are 

 not surprised to find that Mr. Hill has shown that the data 

 for India can be twisted into proving either a maximum or a 

 minimum of rain for each maximum of solar spots, the truth 

 being that a change in the solar heat produces opposite ef- 

 fects in two regions whose geographical conditions are dis- 

 similar. 



Dr. Hunter has shown that at Madras itself the years of 

 little rain, drought, and famine agree with the years of mini- 

 mum sun-spot frequency. Messrs. Hill and Archibald have 

 discovered that in Northern India, between latitudes 20 and 

 30, the winter rainfall corresponds inversely with the period 

 of solar spots i. e., the maximum winter rainfall coincides 

 with the minimum of sun-spots. The failure of these winter 

 rains causes short crops and severe famine in the subsequent 

 season. Assuming that the sun radiates less heat at times 

 of sun-spot maximum, it seems possible to plausibly explain 

 the consequent slight rainfall, In general, in years of maxi- 

 mum sun-spot, the summer rainfall is above, and the winter 

 rainfall below the average, and inversely in years of mini- 

 mum sun-spot. The reality of this connection is endorsed by 

 Buchan, who appeals to the British government to avert dis- 



