DISTURBANCES IMPRESSED UPON THE 
EARTH’S MAGNETIC FIELD.* 
Francis E. Neuer. 
It is now thirteen years since the writer first made a 
long series of experiments, in which an attempt was made 
to reproduce, by means of explosions, the magnetic dis- 
turbances due to solar outbursts. These results were 
finally obtained at my summer home near Hessel, Mack- 
mae County, Mich., during the summer of 1914. 
In these experiments, half a ton of rapid burning blast- 
ing powder and 300 pounds of 40 per cent dynamite was 
used. The expense involved was paid by the Carnegie 
Institution of Washington. 
The magnetic needle and its enclosing ease was fully 
described in a former paper.’ As in the work deseribed 
m the former paper, all possible precautions were taken 
to make the case surrounding the needle air-tight. The 
damping wire dipping into coal-oil in the bottom of the 
glass bottle which formed the enclosing case, was only 
1 em. in length, in order to give to the needle more free- 
dom of motion than it had in former work. The socket, 
provided with leveling serews into which the bottle was 
sealed, was securely clamped to the table. The top of the 
tube of metal within which the suspension fiber was hung 
from a torsion head, was braced by four bars of wood, 
Inclined at an angle of 45° with the vertical. Along these 
bars were four heavy cords, attached to the torsion head, 
Passing down through the table. Upon these cords were 
tr 
* Presented by title to The Academy of Science of St. Louis, Decem- 
ber 6, 1915. 
‘ Variations in the Earth’s Magnetic Field. Trans. Acad. of Science 
of St. Louis, XXII:109-110. 1913. 
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