48 



CLIMATIC CYCLES AND TREE-GROWTH. 



provisionally. It was 700 years old, with coarse, sensitive rings, and was 

 the only one of the group showing the ring for 1915. In comparing 

 these two for larger variations no accordance was recognized and in 

 details cross-identification failed also, due (as afterwards found) to 

 accumulated errors in No. 1. 



No. 2 was then counted and compared with No. 5 with apparent 

 certainty and satisfaction. The former was nearly 6 feet in radius, 

 with small rings, 2,200 years old, and with all but 3 years represented. 

 The last 700 years were thus compared minutely with No. 5 and the 

 earlier parts with No. 1, and one ring (later identified as 699 A. D.) was 

 found to have been overlooked. The earlier parts were later all checked 



D+ 



% 



m 





^/V^^-A/^ 



V 



<w> 



3.5 

 3.0 

 2.5 

 2.0 

 1.5 

 1.0 

 0.5 

 1.0 



.5 



0.5 



< 



1.0 



0.5 





 1.0 

 0.5 



1850 



60 



70 



80 



90 



1900 



10 



FIG. 12. Cross-identification in first five sequoias and gross rings in No. 1. 



against No. 3 and no suspicion of error was discovered. This number 

 was, therefore, taken as the best type of specimen of this group. 

 Large fluctuations of size rarely occur in it. 



No. 3 was next counted by comparison with No. 2. No. 3 has few 

 large fluctuations and large portions of it match No. 2 with the greatest 

 accuracy. Nevertheless, as a standard with which to compare others, 

 it would be misleading, for it frequently omitted rings; in one place 

 7 rings and in another 6 rings are entirely missing, and half a dozen 

 more in singles and in pairs. Yet cross-identification with No. 2 was 

 easy and perfectly convincing as to the location of the missing rings. 



