614 LAMONT: MAGNETIC RESULTS 
at Prague, that the total intensity continues unchanged during 
disturbances, and that the movements observed are to be attri- 
buted solely to the altered direction. 
Later observation appeared, however, to point to the necessity 
of admitting some, although small, alterations in the total inten- 
sity also: this showed itself particularly in the great disturbance 
of April 5-7, 1843. 
The ratio of the changes of inclination and intensity may best 
be taken from a comparative view. 
Diurnal March in February 1843. 
Sun Easterly. Midnight to Noon. | Sun Westerly. Noon to Midnight. 
h. | Inclination. Hor, Int. Total Int. i h. | Inclination. Hor. Int. Total Int. 
12) —242 | 4383 | +067 |12| —0-17 | +065 | +046 
1 — 3°22 + 3:24 +041 | 1 — 1:32 + 2-01 + 0:94 
2) — 2-55 + 2°36 + 0:09 I 2) — 109 + 2°36 + 1:55 
4 — 2:31 + 1:90 —018 || 3 — 0°55 + 162 + 1:40 
6 — 2:76 + 2:39 +001 | 4 — 0-20 + 145 peace 1:54 
7| —3:10 + 2:80 +004 || 5 —004 | +134 + 1:57 
8 — 315 + 2-84 +003 | 6 — 000 | +087 + 0:97 
9 —177 + 140 — 0:20 7 —141 | +289 + 1:83 
01 — 131 + 1:00 — 0:19 | 8 — 0:89 + 2:47 + 1:88 
ll — 0:49 + 0:00 — 0°49 9 — 211 +370 + 2:03 
12 — 017 + 0°65 + 0-46 10 — 1:92 | +324 +171 
‘j9| —242 | +383 | +087 
A scale-division is equal in the inclination to 13/1, and in 
the horizontal and total intensity to 0°00012 and 0-00013 of the 
whole value. The march of the total intensity is, we see, quite 
peculiar; a rapid alteration occurs at the time of the upper and 
of the lower culmination of the sun; throughout the rest of the 
day the intensity is more constant, and is less when the sun is 
easterly, and greater when it is westerly. No magnetic element 
appears to be so exactly, or at least so simply, connected with 
the course of the sun as the total force. We may form to our- 
selves an idea of the alterations which may occur during mag- 
netic disturbances from the following :—On the 5th of April 1843, 
the declination needle passed through an arc of 20/, and the 
horizontal force and inclination needles through twenty-seven and 
twenty-four scale-divisions; while the total force was altered only 
by two divisions, but at midnight it decreased rapidly ten divi- 
sions, and was stationary during great fluctuations of the other 
elements until noon on the 6th of April, when it again rapidly 
increased. It then continued almost entirely without alteration 
during a highly disturbed march of the direction (the change of de- 
