ioi 
be very hazardous to carry it forward any considerable 
length into the future. We may, however, mention that 
our calculations indicate a maximum of declination range 
about 1884, but not so pronounced a maximum as that of 
1871 , 
f>. During our analysis an observation was made by us 
which we think worthy of record, 
It is a well-known fact that the so called eleven-yearly 
oscillations of declination range are at certain times large, 
and at other times small. Thus, for instance, they have 
been large for the last forty years, but they were small 
about the earlier part of the present century. It is clear to 
us from an inspection of the observations, that a series of 
large oscillations is accompanied with an exaltation of the 
base line, or line denoting average efficiency, while* a series 
of small oscillations is accompanied with a depression of the 
same. The result is a long-period curve of the base line, 
the bent period, so to speak, of the eleven-yearly inequality. 
Now, a phenomenon precisely similar occurs in connexion 
with shorter periods. If we take inequalities having a period 
of three or four months, we find that such are alternately 
well developed or of large range, and badly developed or of 
small range ; and that a large range of such is accompanied 
with an exaltation of the base line or line of average effi- 
