AND OF TERRESTRIAL MAGNETISM. 



263 



ways in \\ hich subsequent and previous associated pulses were made up. The enquiry 

 \\.-is confined to the first of tin- previous and suksequent pulses associated with the 

 distu rlx*d days of the 11 ye;n<. That period was preferred because a greater 

 ilefiniteness attached to the individual "character" figures. When international 

 data are taken, the figure assigned to any individual day may be built up in a large 

 variety of ways. 



Table VII. shows the results of the enquiry ; only the days containing tin- main part 

 iC tin- pulses were considered. The data for the subsequent days were derived from 

 S.M. The representative disturbed day is counted as day 0. 



TAHI.K VII. Analysis of "Character" Figures during the First Previous and the 

 First Subsequent Pulses associated with Selected Disturbed Days of 1890 to 1900. 



Disturbed days in Table VII. include all of " character "2 or 1, those of " character" 

 being called quiet ; so that the sum of the disturbed and quiet together necessarily 

 amounts to 660. The distribution one would have had in 660 average days appears 

 under " normal." As regards the number of 2's, days +27 and 27 decidedly over- 

 top their neighlxnirs. The incidence of 2's in the pulses is more alike if we invert 

 the order of days in the previous pulse, i.e., regard days 25 and +25, &c., as 

 corresponding. But in both pulses the marked tendency is for days of moderate 

 disturbance to follow the crest. No significance probably attaches to the fact that 2's 

 are slightly more numerous in the previous than in the subsequent pulse ; because, 

 while the highest " character " figure in the first previous pulse exceeds that in the 

 first subsequent pulse in the case of the 11-year period, it does not do so in the 

 6 -year period. 



16. Table VIII., p. 265, represents the results of an enquiry into the possible varia- 

 tion of the 27-day period throughout the year. The 11-year and 6-year periods were 

 treated separately. The 660 selected days of the former period gave 55 January 

 days and so on. These 55 January days and the subsequent days associated with 

 them are treated as a separate group in Table VIII. The first two columns give the 

 mean character figures for the selected disturbed days of the 12 months, for the two 

 periods. Columns 3 to 8 give the mean character figures for days 25 to 30 subsequent 



