94 Prof. Loomis on the Distribution of Thunder Storms. 
north they are seldom seen except in the south, and from this 
. point they diminish in frequency and brilliancy as we advance 
towards the pole. Beyond lat. 62° the average number of auro- 
ras is reduced to 40 annually. Beyond lat. 67° it is further re- 
duced to 20, and near lat. 78° to 10 annually. If we makea 
like comparison for the meridian of St. Petersburg, we shall 
find a similar result, except that the auroral region is situated 
further northward than it is in America; the region of 80 auro- 
ras annually being found between the parallels of 66° and 75°: 
nited States than they 
are in the same latitudes of Europe. On the parallel of 45°, we 
find in North America an average of 40 auroras annually; but 
in Europe less than ten. 
GEOGRAPHICAL DISTRIBUTION OF THUNDER STORMS. 
_ The geographical distribution of auroras is believed to be in- 
ey in to the geographical distribution of thunder 
storms. ; 
number of y ears embraced in the comparison; and column 6th ie 
shows the authority for the statements. ; 
f 
Taste VI.— Average number of days of Lightning annually. ~ i 
Place. Latitude | Longitude, ved As oe Authority. : 
ae 
Georgetown, Guiana 649 | 5811 W.| 60| 11. |Brit.Guiana Met,Obs.1846-56 
Laks ll 8 5 ; 
went hide 120 |77 2Wi o Arago Met. Essays, p. 109. 
Abyssinia, 13 37 ae ys, P 
138 4 | 8016E,| 144 
Central Africa, [12 to 1sl4E.toaW.| 65 
te 
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Barth’s Central Africa. 
