334 Prof. E. Loomis on the Aurora of 1859. 
It is not improbable that the line which divides the stations 
at which the extreme deviations of the magnetic needle gene- 
rally occurred earlier than at Gottingen, from those stations at 
which the extremes generally occurred later than at Gottingen, 
differs considerably from a great circle of the earth; but if we 
regard it as an arc of a great circle, then its direction must be 
m about N. 62° W. to S. 62° E., indicating a progress of the 
electric wave from N. 28° E. to 8. 28° W. 5 
It was stated on page 326 that Mr. C. V. Walker, from a dis- 
cussion of the observations on the lines of telegraph in England, 
has arrived at the conclusion that in the S.E. part of England 
there is a stream of electricity drifting across the country from 
N. 42° E. toS. 42° W. We have now found that the irregular de- 
flections of the magnetic needle, which are so remarkable during 
auroral displays, do not occur everywhere simultaneously, but 
are generally propagated over the surface of Europe in a direction 
from N. 28° KE. to S. 28° W. It is possible that a more extende 
series of observations would show that these two directions are 
identically the same; but it is not improbable that the direction 
in England is somewhat different from that in Central Europe. 
ime of greatest and least deflection at Dublin is on an 
average five minutes later than at Gittingen. Now Dublin 1s 
situated 222 miles from the great circle above mentioned, pass 
ing through Gottingen, indicating a progress of the electric wave 
of about 2700 miles per hour. The time of the extreme devia 
tions at Upsala is on an average three and one-third minutes 
earlier than at Géttingen; while Upsala is situated 644 mules 
rom the great circle above mentioned, indicating a progress of 
the electric wave equal to 11,000 miles per hour. If we make 
a like comparison for each of the other stations, we shall obtain 
velocities very unequal in amount. We thus perceive the diflt 
culty of determining the average rate of progress of the electri¢ 
wave. Sometimes the observations may be explained by supp?* 
ing asingle broad current of electricity flowing over Europe — 
.E. to S.W. as in the case of Nos. 10, 23, 24, 26, 28, ite 
65, 69, 71, etc. Occasionally the progress appears to be main’y 
from 8.W. to N.E., as in the case of Nos. 58 and 70. 
At other times the effect takes place simultaneously from Up- 
sala to Milan, or at least within a period of five minutes, 51? 
the case of Nos. 5, 7, 9, 11, 12, 18, 14, 19, 20, 29, 31, eto, 
At other times it seems necessary to admit the oxime 4 
several currents moving in different directions, and proba 4 
with unequal velocities, as in the case of Nos. 15, 37, 98, *% 
45, 50, 51, 54, 57, 62, 74, ete. ee 
Of the seventy-six cases of magnetic disturbance contained is 
the preceding catalogue, thirty-three occurred on days when “a 
aurora was recorded at some one of the stations. Some of t 
