CONCEENED IN PEODUCINa THE GEEATEE MAGNETIC DISTIJEBANCES. 627 
Table II. — Exhibiting the connexion between the small movements of the declination 
and those of the horizontal force in the various disturbances. 
Date of disturbance. 
Number of 
corre- 
spondences. 
Number of 
non-corre- 
spondences. 
Doubtful. 
1S58. March 12 — 16 
18 
1 
5 
April 9 — 12 
24 
0 
5 
June 22 — 24 
13 
0 
1 
October 27 — 29 
15 
0 
0 
December 4 — 6 
12 
1 
1 
1859. February 8 — 10 
13 
2 
1 
February 26 — 28 
19 
0 
2 
April 21 — 23 
14 
0 
1 
April 29 — May 1 
15 
0 
1 
May 19—21 
14 
0 
0 
June 8 — 10 
13 
0 
1 
July 11 — 13 
10 
0 
5 
October 12 — 14 
8 
1 
2 
October 17 — 19 
19 
0 
2 
December 13 — 15 
9 
0 
1 
I860. March 26 — 30 
29 
0 
2 
April 9 — 1 1 
22 
0 
5 
April 13 — 15 
15 
1 
1 
June 29 — July 6 
28 
0 
3 
August 6 — 13 
65 
12 
46 
September 7 — 8 
7 
0 
0 
Sums... 
382 
18 
85 
It will be seen from this Table that, in the great majority of cases, a peak in the decli- 
nation corresponds to a peak in the horizontal force, and a hollow in the one to a hollow 
in the other. It is proper to mention that the peaks and hollows here observed are those 
which represent sudden changes of short duration ; for if we take for comparison some 
prominent peak or hollow in the one curve having a long period, we shall be much less 
certain of finding a corresponding phenomenon in the other. 
12. When the peaks and hollows of the horizontal force and those of the vertical force 
are compared together, the result is that a peak invariably corresponds to a peak, and a 
hollow to a hollow ; and even when large prominences of long duration are taken, the 
correspondence between the two curves is very remarkable. 
The same connexion, therefore, which subsists between the sudden movements of the 
declination and those of the horizontal force, holds still more strikingly between those of 
the two forces, 
13. The disturbance of August — September 1859 has been purposely left out of 
Table II. ; in the following Table this great disturbance has been broken up into parts, 
for each of which the behaviour of the peaks and hollows is compared with the general 
appearance of the curve. 
