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DR. CHARLES CHREE: SOME PHENOMENA OF 



minimum for the day thus often differ much from the largest and smallest hourly values. 

 Then disturbed day phenomena are often in the highest degree irregular, and it is 

 thus natural to expect a much greater variability in the times of maximum and 

 minimum. The more variable these times, and the more variable the type ol 

 disturbance, the smaller will the ratio of the inequality range to the absolute range 

 tend to be. It thus appeared desirable to calculate the values of the ratio for the 

 disturbed days in the several elements, and to compare them with the only corre- 

 sponding quiet and ordinary day data available, those for D. This comparison is 

 effected in Table X. It contains two sets of values. The first set represents the 

 arithmetic mean values of the ratio (inequality range/absolute range) calculated for 

 the 12 months individually. The second set was derived from the seasonal diurnal 

 inequalities and the corresponding mean absolute ranges. 



TABLE X. Values of (Inequality Range -f- Absolute Range). 



Difference in the type of a diurnal inequality between the months comprised in a 

 season tends to reduce the inequality range for the season below the arithmetic mean 

 of the ranges for the contributory months. Thus if the type of the diurnal inequality 

 in individual months were largely dependent on " accidental " features of individual 

 disturbances in other words, if there were a large pseudo-element the second set of 

 values in Table X. for disturbed days would be much smaller than the first set. The 

 second set, it will be seen, is the smaller in all cases, the most conspicuous example 

 being the winter value for H ; but in most cases, especially in V, the difference 

 between the two sets of values is small. 



