86 IOWA ACADEMY OF SCIENCES. 



the balance of the year, except a large-sized group which 

 later formed a stream of small spots in October. The 

 closing two months of 1900 were absolutely quiet. 



1901. 



The year now under review marks the end of the eleven 

 year cycle of solar activity, the minimum having in all 

 probability been reached by the middle of the year. 



In August some few short-lived spots broke out in high 

 southern latitude, which would indicate that the new cycle 

 had commenced, as it is now fully demonstrated that spots 

 of a new curve of activity first appear in high latitudes and 

 gradually approach the equator as the period progresses, 

 until as the minimum is reached again, the evidences of the 

 dying cycle are found in zones within the equatorial 

 regions. 



During the year 1901 there were 212 spotless days out of 

 a total of 269 days of observation, or nearly seventy-nine 

 per cent. 



The most noticeable characteristic of the year's record 

 was the sudden outburst of a large spot in May, which was 

 easily visible to the naked eye; its low latitude indicated 

 that it belonged to the expiring cycle rather than to the 

 incoming period. Coming at a period of absolute quies- 

 cence, it was certainly a surprise to observers of solar phe- 

 nomena. It was the final outburst of the pent-up forces 

 which brought the minimum to an end. 



1902. 



During the first half of January an average sized group 

 crossed the visible disc near the equator; this was followed 

 by a period of perfect quiescence — an entire absence of 

 spots and faculae — lasting until March 1st, when a fairly 

 large group in high north latitude, belonging to the new 

 cycle, completed the transit. Another period of prolonged 

 tranquility followed, which lasted until May 23d, on which 

 date a normal spot appeared, which in all probability was 

 a return of the March group, but which was not visible in 



