CONCERNED IN PEODUCINO THE GREATER MAGNETIC DISTURBANCES. 625 
producing the first, the peaks and hollows should be similar in character to the general 
effects of the force. The following example will explain what is meant. 
If we have a force which simultaneously and for a lengthened period of time raises 
up the curves of all the three elements nearer to the top of the paper, and if the peaks 
and hollows denote changes taking place in the intensity of this force, then all the three 
elements should exhibit peaks at once, or hollows at once. But if, on the other hand, 
the general appearance of the curves represents the declination as raised up while both 
the other elements are depressed, then a peak in the former should correspond to a 
hollow in the latter two. 
9. I requested Mr. Chambees, Magnetical Assistant at Kew, to note his impression of the 
general appearance of the disturbance curves of most importance for the years 1858, 1859, 
and 1860 ; and the following Table is the result. The sign + means that the curve is raised 
towards the top of the paper, the sign — means that it is lowered towards the bottom. 
Table I. — General appearance of Disturbance Curves. 
Date. 
Character of disturbance. 
Declination. 
Horizontal force. 
Vertical force. 
1858. March 28—29 

+ 
+ 
April 9—10 
— 
— 
— 
June 23 — 24 
+ 
— 
— 
July 5 — 6 
0 
— 
— 
October 27 — 28 
indefinite. 
indefinite. 
+ 
December 4 — 5 
+ 
+ 
t 
1850. February 9 — 10 
+ 
0 
1 
February 9 — 10 
+ 
0 
+ i 
February 26 — 27 
— 
indefinite. 
April 21 — 22 
— 
— 
— 
April 21 — 22 
+ 
+ 
April 29—30 
— 
— 
— 
May 19—20 
— 
— 
— 
June 8 — 9 
— 
— 
June 8 — 9 
indefinite. 
+ 
+ 
July 11 — 12 
0 
July 18—19 
— 
0 
— 
August 28 — 29 
— 
+ 
+ 
September 1 — 2 
— 
+ 
+ 
September 2 — 3 
— 

September 3 — 4 
— 
— 

October 12—13 
— 
— 
indefinite. 
October 17 — 18 
+ 
+ 
+ 
October 17 — 18 

+ 
+ 
October 18 — 19 

October 18 — 19 
+ 
December 13 — 14 
December 13 — 14 
indefinite. 
0 
_ 
December 14 — 15 

0 
+ 
I860. March 28 — 29 
— 
+ 
March 29 — 30 

April 9 — 10 
— 

April 9 — 10 
+ 
+ 
.July 4 — 5 
+ 
+ 
+ 
July 5 — 6 
— 
— 
August 6 — 7 
indefinite. 
— 
0 
August 7 — 8 
0 

August 8 — 9 
— 

August 9 — 10 
0 
— 
August 12 — 13 
— 
_ 
August 12—13 
— 
+ 
September 7 — 8 
4 Q 2 
