DOUGLASS 



PLATE 12 



DIFFERENTIAL PATTERNS. 



rr.^Sunspot Nos. 1610-1910 at 11.4. 

 b. 57 European trees, 1830-1910 at 11.4. 



80 European trees, 1800-1910 at 11.4. 



South Sweden, 1830-1910 at 12.0. 



Vermont group, 1650-1910 at 11.3. 



Flagstaff group, 500 years at 11.4. 



Flagstaff group at 23.5 years. 



Norway, 1740-1910 at 23.8 years. 

 ?'.f Austria, 1830-1910 at 22.0 years. 



c. 



d. 

 e. 

 f. 



Norway, N-2, 400 years at 33.0. 



Vermont, 250 years at 32.5. 



Sweden, 1740-1910 at 37.0. 



Sequoia, 1300-250 B. C. at 33.0. 



Flagstaff, 500 years at 33.0. 



Sequoia, 3200 years at 101. 



Flagstaff, 500 years at 120. 

 q. Standard 5-year period at 5.0 years. 

 r. 5 to 10 year logarithmic variable 

 period at 8.0. 



J- 

 k. 

 I. 

 m 



o. 



P. 



