THE CURVE OF THE BIG TREES. 



145 



only +1.3 years. If the sum of all his divergences, whether plus, minus, or zero, be taken 

 it amounts to 262, or an average of +5.7. This is a trifle over 0.333 per cent of the 

 average age of the trees. The net result is that in these 46 measurements, which are a 



Table 4. — The effect of recounting the rings of growth upon the apparent age of the sequoias of California. 



* This measurement was made by mistake at a part of the tree where a portion of the outer 

 rings had decayed. Of course it was not used, but it is added here merely to illus- 

 trate the dangers that must be guarded against. 



t This means the difference between the apparent age of the tree on the first count along two 

 different radii as indicated by the numbers 1262 for 371 A and 1263 for 371B. 



fair sample of all, the probable difference between X's recount and the original count of 

 himself or of one of the others was only 0.333 per cent, and might be either an excess or a 

 deficiency, with a slight tendency toward getting more rings in the recount than in the 

 original count. This tendency, however, amounts to only 0.1 per cent. With Y the 

 case is similar, but as he was more careless than his two companions his divergence is 

 11 



