ABSOLUTE OBSERVATIONS AND ADJUSTMENTS. 



129 



The corrected hourly means having been reduced by this table, the values were entered 

 into the International Schedules with corresponding movement symbols.* 



The extreme values and daily range were extracted from these results only, not from the 

 individual observations, as in the case of the other two instruments. Daily, hourly, and 

 monthly averages were then finally computed. 



The readings on term days were merely copied into the Schedules after correction and 

 reduction, and plotted as curves. (Plates 1 to 23.) 



OBSERVATIONS ON SELECTED DAYS. 



In conformity with the decision of the Vienna Conference, the instrumental readings on 

 certain days enumerated by Dr. Wild have been copied out, reduced, and measured, in order 

 to give the undisturbed diurnal variation of the magnetic elements. These observations have 

 been entered according to Gottingen mean time, although they were not made precisely at 

 the Gottingen hours, excepting in the case of term days. 



The rule followed throughout has been to enter observations at Ih., 2h., 3h., a.m., &c., Fort 

 Rae mean time as 9h. 23m., lOh. 23m., llh. 23., a.m., &c., Gottingen mean time. 



These observations have been grouped in pairs of months in compliance with Circular 

 No. 39 issued by Dr. Wild, and the final curves of diurnal variation drawn from them. 

 (Plates 29 to 32.) 



Table 12 exhibits the average values of the Horizontal, Vertical, and Total intensities as 

 well as the Inclination and Declination at Fort Rae, for the year 1882-83, as derived from 

 the means of these selected days. 



Table 12. 



For selected days of disturbance the corresponding values have been extracted from the 

 Schedules and entered to the corresponding Gottingen mean time, including also the reduced 

 additional observations made at Fort Rae when a disturbance was seen to be taking place. 



Kew Observatory, 

 April 4, 1885. 



G. M. WHIPPLE. 



* See p. 125. 



A 17420 



