174 DR. C. CHEEE-. AN ENQUIRY INTO THE NATURE OF THE RELATIONSHIP 



differs widely from European stations. At Kew, for instance, D, H, V, and I all 

 show a large variation in the amplitude of the diurnal inequality throughout the 

 year. The range is three or four times as large at midsummer as at midwinter, and 

 the way in which the range, or the sum of the 24 differences, varies throughout 

 the year is pretty similar for all the elements. Thus, assuming that the mean diurnal 

 inequality for the year were derivable from a potential, one could obtain a fair first 

 approximation to the mean diurnal inequalities for individual months by multiplying 

 this potential by appropriate numerical factors. 



How exceedingly far this is from being the case at Batavia will be seen on 

 inspection of Table XVII. This gives the sum of the 24 differences in the diurnal 

 inequalities for each month of the year, with their mean, and the sum of the 

 24 differences in the mean diurnal inequality for the year. Batavia being in the 

 Southern hemisphere, May to August are the " winter" months. 



The D data in Table XVII. proceed, on the whole, like European data. In V, too, 

 the lowest value occurs in the winter months, but there is likewise a low value in 

 December. While the average value for I from the four winter months is below the 

 mean for the year, the lowest values of all occur in November and December. In H, 

 three out of the four winter months show values above the average, while the four 

 summer months are all below the average. Thus no two elements behave alike, and 

 the phenomena exhibited by H are more nearly opposite than parallel to those 

 observed in high latitudes. 



TAHLK XVII. -Batavia, 1887-1898 (Unit 1' in D and I, ly in H and V). 

 Sum of the ~24 Hourly Differences in the Mean Diurnal Inequality for the Month. 



