360 Transactions of the Boyal Society of South Africa, 
indicate that the daily range is not very constant, a notable deviation 
occurring on September 25th. The horizontal Hne drawn through the 
various curves corresponds to a dechnation of 24° W. Distances above 
the line show the easterly variation. The points 1'8', etc., above and 
below the line give the value in minutes of 1, 2, 3 divisions of the scale. 
For any adequate discussion of the magnetic variation at any plane at 
least one year's complete records are necessary, for the times at which the 
variation changes from the extreme eastward or westward position alters 
with the time of the year. In the curves given the whole period extends 
only over one-third of the year, and the tendency appeared to be directed 
to putting the time of the first max. — i.e., the extreme westerly position 
earlier in the day. From August 11th to November 18th the time 
