A STUDY OF CORRELATIONS AMONG TERRESTRIAL TEMPERATURES. 347 



contribute more than half to the making up A, the correlation number. Of these 9, 

 the two extremes, India- Australia and Manila-Australia, are so distant from each other 

 that they should be included in the class not subject to any common cause of change of 

 temperature. Their contributions to hA are : 



India- Australia *A = - li.O ww'r =228 



Manila-Australia " = - 0.7 " = 228 



Sum - 3.7 456 



We now have the following equations for the mean value of that portion of the 

 fluctuations of mean annual temperature which we may attribute to a general cause 

 affecting the whole earth : 



This gives 



< = .0' 



T„ = ± 0"065 C. 

 This fluctuation, if regarded as real, is too minute to produce any important mete- 

 orological effect. That it may well arise i'rom the accidental deviations is shown by 

 the fact that, had Kingston been omitted, v would have come out negative, indicating 

 a tendency toward an equalization of the general temperature of the globe from year 

 to year. But there is nothing to justify us in rejecting Kingston for this reason, 

 though a careful analysis might show that we have given it greater relative weight 

 than it is entitled to. The same remark would, however, apply to Havana, the 

 result of which is markedly in the opposite direction from that of Kingston. 



§ 10. Tmie Correlations in Animtil World Temperatures. 



Returning to Table VI, it is noticeable that the larger outstanding departures t 

 do not seem to be scattered at random, but are rather collected in groups of like alge- 

 braic sign, as if they were the result of a fluctuation having a period of several years. 

 It would Ije easy to represent them by the ordinates of a sinuous curve, but a conclu- 

 sion based on this method would be altogether unreliable. We shall therefore apply 

 the method of time correlation, developed in § (i, which will bring out with numerical 

 exactness any period that may exist, or any periodic tendency. The numerical process 

 is shown in the following lines, the numbers of which are formed as follows : Starting 



