In seeking further evidence of sunspot correlation, advantage was taken of certain statistics recorded while measuring the various sections. Before making the measures or identifying the rings in any way, the groups of rings larger than the average were sought out and
Fig. 26.—Dates of large rings in 80 European trees compared with sunspot curves. Ordinates give number of trees in total of 80 showing maxima in respective years.
Fig. 27.—Tree-growth at Windsor, Vermont, showing measures uncorrected; same standardized and smoothed, and sunspot numbers displaced 3 years to left.