’ 
CORRELATION WITH SUNSPOTS. 79 
crosses were placed upon the central ring, which was usually the largest 
of the group. These crosses are well shown in plate 4, 8. Their dates 
were noted during the measuring. In figure 26 the ordinates give the 
number of maximum marks found in each date throughout the whole 
jae. = 
Se SE TEP TE oe L\ z= 
7 DE, SPA BEAN 7 ae Wan 
ce. AA FETOCSNE ZEN 5 se 
: ‘ otiys 
38 
eae i 
10 § 
1830 7840 7850 7860 7870 
tad S 
i 1 Ors ae a ~ nx F712 
LT SUN A J F 
U bev 3 
2 3§ 
ak i | 
= eo. [— 
ee 
eae 1 ; 
rm NM ae 
ay J ~~ \f \ epee Lhe, § 
70 - 10§ 
a M60 1890 7900 79/0 
Fic. 28.—Smoothed quarterly rainfall (upper curve), sunspot numbers (center), and 
tree growth (lower) at Windsor, Vermont, 1835 to 1912, 
80 sections. The more recent dates show higher crests because there 
aremore trees. In the second line is the sunspot curve. The matching 
of the crests of the two curves is unmistakable. The secondary tree- 
crest at sunspot minimum is very regular, as would be expected from 
the inclusion of the three groups of figure 24, some of which are evident 
reversals. This test is only qualitative, but seems to the writer to offer 
substantial support to the quantitative relation shown in figure 25. 
Windsor (Vermont) correlation.—An interesting sidelight is thrown on 
this type of correlation by the American curves from Windsor, Vermont. 
