IN THE LARGER MAGNETIC DISTURBANCES. 
167 
the year 1843 has been shown to be that of least disturbance, and 1848 of greatest ; 
and we have here some additional evidence of a general cause operating over the 
whole globe to produce a minimum magnetic effect in 1843 progressing towards a 
maximum in 1848. In judging of the fulfilment of the general law and of the degree 
of accordance of the ratios at the two stations, it is to be borne in mind that three 
years only are complete years of observation at each station, and that in the other 
three years at each station the ratios are necessarily computed from the portions of 
those years to which the observations are limited ; also, that although the observa- 
tions were everywhere made simultaneously, as stated above, yet that the cessation 
on Sundays was regulated by local time ; and as the Saturdays’ observations were 
closed at midnight, and the Mondays’ observations commenced at 1 a.m. civil time, 
there are a certain number at each station which have none corresponding at any 
other. 
Table II. contains the ratios of the numbers and aggregate values of the disturb- 
ances, divided into their westerly and easterly components, to the average annual 
number and aggregate value. 
Table II. 
Years. 
St. Helena. 
Cape of Good Hope. 
Westerly. 
Easterly. 
Westerly. 
Easterly. 
Numbers. 
Aggregate 
values. 
Numbers. 
Aggregate 
values. 
Numbers. 
Aggregate 
values. 
Numbers. 
Aggregate 
values. 
1841 
0-95 
1-07 
1-00 
1-08 
1842 
0-91 
0-92 
1*02 
0-96 
1*14 
1-16 
1-39 
1-40 
1843 
0-75 
0-70 
0-89 
0*86 
0-56 
0-52 
0-59 
0-54 
1844 
0-89 
0-91 
0-90 
0-92 
0-97 
0*95 
0-80 
0-77 
1843 
0-96 
0-94 
1-03 
1-04 
0-96 
0-96 
0-88 
0-84 
1846 
1-07 
1-04 
1-02 
1-05 
1-42 
1-36 
1-36 
1-36 
1847 
1-43 
1-49 
M4 
M7 
If we separate the whole number of observations at St. Helena and the Cape into 
their easterly and westerly components, we find that each of the two divisions singly, 
indicate the same periodical law which they did when combined, viz. a fall to a 
minimum in 1843, from whence an increase towards a maximum in 1848 takes place; 
and this is apparent both in the number of observations disturbed and the amount of 
the disturbance. By an easterly disturbance is to be understood, that the end of the 
needle which points north is disturbed from its normal place towards the east, and 
vice versa, and this whether the mean declination has an easterly or westerly value, 
and whether the station be in the northern or southern hemisphere. 
Table III. contains the ratios of the westerly to the easterly disturbed observations 
in each year, in numbers and values. 
