Page:Climatic Cycles and Tree-Growth - 1919.djvu/121

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DOUGLASS   PLATE 11

Climatic Cycles and Tree-Growth Plate 11.jpg

A. Periodogram of standard 5-year period.

B. Periodogram of mixed periods.

C. Periodogram of sunspot numbers, 1610-1910.

D. Periodogram of Flagstaff 500-year record, to show cycles between 4 and 15 years of length.

E. Periodogram of same continued to 25 years.