A STUDY OV COKIIELATIONS AMOXG TERRESTRIAL TEMPERATURES. 



345 



The positive correlation shown by A is so clearly marked as to leave no doubt, a result 

 which accords with what we might anticipate from the geographical proximity of the 

 stations. 



We next investigate the result when the four Indian stations are combined into a 

 single mean, which is found in the last column of Table V. The general world-de- 

 parture then found is shown in column t of Table VI, and the computation of the two 

 series whose difference shows the correlation is shown in the last two columns of the 

 table. Summing by terms as before, we have the following numbers : 



I 

 I 



We thus have for the entire period of investigation 



A= 127.9 



The value of the general fluctuation is thus reduced to 



T„ = ± 0°.07 



a quantity not greater than its probable error. 



But we still cannot assume that all the regions are so distant from each other as 

 to be unaffected through an entire year by any common terrestrial cause, especially 

 the winds. Considering first the proximity of the stations, we notice that Havana 

 and Kingston may be regarded as in the same region with each other, and with the 

 United States. Moreover, the Southeastern Asiatic and Australian stations are so 

 linked in a geographical series that we cannot regard each as necessarily independent 

 of that next to it. On the other hand North America, South America, Apia and the 

 Asiatic-Australian series form four sets which we cannot deem to be correlated except 

 through the action of a cosmical cause, presumably fluctuations of the sun's radiation, 

 which would affect all the stations, how widely soever separated. We therefore inquire 

 whether the correlation we have found is or is not quite general for the earth by 

 correlating the stations in pairs by the method shown in § 5. Beginning with the 

 widely separated stations we correlate the three North American regions, United 



