Smithsonian Report, 1947.— Nicholson 



PLATE 2 



'mm 



1926 JAN. 24 



1946 JULY 26 



1947 MAR. 9 



100,000 MILES 



%*■*»" 





1947 APRIL 7 .. 



THE FOUR LARGEST SUNSPOT GROUPS 



The last two photographs are of the same group showing its development during one solar rotation. 



