ABSOLUTE DAILY RAXCIiS. 131 



CHAPTEK VI. 

 ABSOLUTE DAILY RANGES. DAILY MAXIMA AND MINIMA. 



38. By the absolute range of an element is meant the excess of the .absolutely largest over the absolutely 

 smallest value met with during the 24 hours. The term absolute is' added to indicate that the quantity 

 considered is not the range of the regular diurnal inequality, nor the range derived from mere hourly 

 readings. The absolute ranges arc at once derivable from the daily maxima and minima given in the 

 tables of tabulated values, but for convenience of reference they have been collected and presented in 

 Tables XLVI, XL VII, and XL VIII. 



It is of course impossible ever to say with certainty, in the case of an absolutely isolated station like 

 Winter Quarters, what may have been taking place during the time of changing papers. There is 

 always the possibility that, in the course of a few minutes during which no trace was being recorded, an 

 element may suddenly have changed and then reverted to near its primitive value. But even in the 

 Antarctic, though large sudden changes were not of very rare occurrence, it was very unusual for them to 

 occur singly, and one could usually feel fairly confident that neither the daily maximum nor the daily 

 minimum had occurred whilst there was no paper on the drum. When, however, the interval between 

 successive sheets was considerable, as occasionally happened, or when the trace was highly disturbed 

 about the time of changing, there might be considerable doubt as to whether a maximum or minimum 

 might not have occurred in Declination or Horizontal Force. 



In Tables XLVI and XL VII, relating respectively to D and H, ranges are usually given whether the 

 record for the day was complete or not. There are, however, omissions on a few days when the traces were 

 confused or indistinctly visible. Figures inside [ ] brackets relate to days when the record was incomplete, 

 but when the general appearance of the curve seemed to warrant the belief that both the maximum and 

 the minimum for the day were actually recorded. Figures inside ( ) brackets are for days of incomplete 

 record, when appearances suggested that either the maximum or the minimum, if not both, was unrecorded. 

 The combination > + means that the trace went beyond the limit of registration in the direction of 

 element increasing, while > - means that the trace exceeded the limit in the direction of element 

 diminishing. When both limits were exceeded, the combination > is employed. The sign * denotes 

 that the trace was too confused to decipher, while denotes that no trace, or only a few hours' trace, 

 existed. Figures preceded by > are certainly, and those in ( ) brackets probably, under-estimates of the 

 true range. 



In the case of D, and still more in that of H, the number of days when the record was incomplete was 

 so considerable, and the cause was so frequently due to the limits of registration being exceeded, especially 

 in Summer, that a very imperfect idea of the average amplitude would have been derived if days of 

 incomplete record had been omitted. This consideration did not, however, apply to V, as loss of record of 

 this element very seldom arose merely from the daily amplitude being large. The almost invariable cause 

 was defective action in the magnetograph, or loss of temperature trace, and so ignorance of the 

 temperature correction. There was thus no reason to regard the ranges derived from days of complete 

 record as below the average size. It was thus decided to give maxima and minima and absolute ranges 

 only for the days of complete record. These ranges appear in Table XLVIII, and means are given for the 

 separate months. In February, October, November, and December, 1 903, however, the number of days 

 from which the means are derived are so small that the figures possess but slight significance. 



