428 
]ME. B. STEWAET ON THE GEEAT MAGNETIC DISTIJEBANCE 
as well as the larger drawing exhibited at the Meeting on November 11, was deduced 
from an exact reduction of the recorded times. 
“ It has been very gratifying to me to learn that our friend Mr. Hodgson chanced to 
be observing the sun at his house at Holloway on the same day, and to hear that he was 
a witness of what he also considered a very remarkable phenomenon. I have carefully 
avoided exchanging any information with that gentleman, that any value which the 
accounts may possess may be increased by their entire independence.” 
On calling at Kew Observatory a day or two afterwards, Mr. Caerington learned that 
at the very moment when he had observed this phenomenon the three magnetic elements 
at Kew were simultaneously disturbed. If no connexion had been known to subsist 
between these tAvo classes of phenomena, it would, perhaps, be wrong to consider this 
in any other light than a casual coincidence ; but since General Sabine has proved that 
a relation subsists between magnetic disturbances and sun spots, it is not impossible to 
suppose that in this case our luminary was taken in the act. 
This disturbance occurred as nearly as possible at 11^' 15™ a.m. Greenwich mean time, 
on September 1, 1859, aftecting all the elements simultaneously, and commencing quite 
abruptly. 
The first or most abrupt portion of the disturbance lasted only about three minutes 
for all the elements ; but after that there was a more gradual change in the same direc- 
tion before the curve turned. This more gradual continuation of the first sudden move- 
ment lasted about seven minutes for all the elements. 
The westerly declination was increased — 
By the first, or three-minute movement, about . . 
By the last, or seven-minute movement, about . . 
In all, the disturbance increased the westerly! 
declination J 
6-6 
6-6 
13-2 
The horizontal force was diminished — 
By the fii’st movement .... 
By the last movement .... 
In all, it was diminished by 
The vertical force was also diminished — 
By the fii’st movement .... 
By the last movement .... 
In all, it was diminished by 
*005 of the Avhole. 
•0025 of the whole. 
•0075 of the whole force. 
•0008 of the whole. 
•0005 of the whole. 
•0013 of the whole force. 
It thus appears that the direction of this disturbance was the same for all the elements 
as that of the two great disturbances, the latter of which took place not many hours 
afterwards. 
The leading features of this great storm appear to suggest something regarding the 
