AND OF TERRESTRIAL MAGNETISM. 



253 



days by an interval of from 84 to 79 days, but complications would have ensued, 

 tacause a day 80 days, for instance, prior to a selected April day may fall in January 

 or in February. 



A general idea of the phenomena disclosed by Table III. will be most easily 

 grasped by consulting fig. 2. The central vertical line in the figure applies to the 

 representative days, disturbed and quiet. Abscissae, measured from this line, represent 

 the interval in days from the representative day, time previous being measured to 



i 



-0-5 



6 



Fig. 2. 



the left, and time subsequent to the right. The numeral attached to any particular 

 point on a curve signifies the interval in days from the representative day, whether 

 previous or subsequent. The ordinate represents the algebraic excess of the 

 " character " figure over the corresponding normal " character " figure in the third 

 line of Table III. 



The representative disturbed day had a "character" 1'321. Its excess, 0'664, 

 over the corresponding normal value (0'657) is represented by the positive ordinate 

 marked 0. The representative quiet day, on the other hand, had a "character" of 



