T KEW OBSERVATORY, 1898 TO 1912. 159 



The natural inference is that a comparison of winter and summer based on '1912 

 would not be very wide of the mark, and consequently that the difference between 

 these two seasons is normally less at Edinburgh than at Kew. 



Some individual months, however, of 1912, at Kew, diverged far from the normal. 

 January, for instance, had an abnormally high potential, while March and December 

 had abnormally low potentials, and the corresponding figures for Edinburgh are at 

 least suggestive of a like phenomenon there. On the other hand, while the Kew 

 October potential in 1912 is abnormally high, Edinburgh presents apparently exactly 

 the opposite phenomenon. 



Coming to the Fourier analysis of the diurnal inequality, we have the following 

 results in the case of the mean diurnal inequality for the year, employing c a (equivalent 

 to Messrs. CARSE and SHEARER'S ) to denote the mean daily value. 



TABLE XII. Comparison of Edinburgh and Kew. 



As Table IX. shows, the value of c 2 at Kew in 1912 was fairly normal, though a 

 little above the average. But the 1912 value of 2 was the largest of the 15-years, 

 while the 1912 values of c l and a. were exceeded, the former only once, and the latter 

 only twice. 



Thus, so far at least as Kew is concerned, 1912 was hardly a year which one would 

 have selected as representative of average conditions. Unless, however, there is a 

 remarkable differeiice between all and quiet day results, there can be but little 

 doubt that the 24-hour Fourier-wave is of greater relative importance at Edinburgh 

 than at Kew. 



