OX THE PERIODICITY OF THE AURORA BOREALIS. 



211 



FORMULiE FOR THE MEAN ANNUAL CURVE, AT DIFFERENT PLACES. 



[2**4-123° 2']4-1.13sin. 

 [2**4-110° 48']+1.54 sin. 

 [2rt«4- 60°17']4-3.32sin. 

 [2«*4- 57° 40']4-3.72 sin. 

 [2**4- 12° 8']4-2.13 sin. 

 [2**4- 88°42']4-6.16sin. 

 [2«<4-264°47']4-1.54sin. 

 [2«?4-127°44']4-3.07sin. 

 [2 * *4-261° 54']4-2.84 sin. 

 [2**4-150°ll']4-3.86sin. 

 [2««4-182°59']4-1.02sin. 

 [2**4-264° 2']4-2.29 sin. 

 [2««4-114 b 41']4-4.97sin. 

 [2««4-lll°28'J4-6.61sin. 

 [2**4-109°24']-)-2.71sin. 

 [2 n t-\-\ 15° 41']4-4.99 sin. 

 [2**4- 90° 48']4-5.80 sin. 

 [2**4- 95° 52']4-5.99 sin. 

 [2**4-119° 6']4-4.57 sin. 

 [2 « *4-140° 37']4-3.43 sin. 

 [2**4-102° 2'J4-4.47 sin. 



[2 7rH-125°49']4-4.24sin. 

 [2**4- 48° 17']4-5.44 sin. 

 [2**4-351° 7']4-3.64 sin. 

 [2**4- 87°10']4-4.86sin. 

 [2**4-189° 8']+5.01 sin. 

 [2**4- 33° 2']4-4.29 sin. 

 [2 * *+101° 49']4-5.69 sin. 

 [2««4-312°57']4-2.77sin. 

 [2**4- 98°33']4-4.10sin. 

 [2 * <4-352° 2§']4-5.1 1 sin. 

 [2 * *4-249° 47']4-3.47 sin. 

 [2**4-300° 5']+5.49 sin. 

 [2«?4-119°46']4-5.32sin. 

 [2 n t-\- 63° 37']4-4.85 sin. 



[4**4-206° 7']4-1.41 sin. 

 [4**4-316° 6']4- .64sin. 

 [4**4-336°25']4- .71 sin. 

 [4«<4-315°22']4-1.68sin. 

 [4re<4-259°57']4- .52 sin. 

 [4**4-326°57']4-1.96sin. 

 [4**4-340° 57']4-1.47 sin. 

 [4**4-300° 0']+2.83 sin. 

 [4**4-339° 9'J4-1.28sin. 

 [4**4-320°52']4- .95 sin. 

 [4**4-31 2° 45']4- .57 sin. 

 [4«*4-324°51']4- .54 sin. 

 [4**4-315° 42']4~ .83 sin. 

 [4a<4-304°27'J4-2.55sin. 

 [4**4-114° ll']4-l.ll an. 

 [4**4-317° 28']4- .76 sin. 

 [4**4-303° 9']4-1.31 sin. 

 [4«*4-308°42']4- .57 sin. 

 [4«<4-321°58']4- .86 sin. 

 [4**4-313° 35']4-2.03 sin. 

 [4**4-310°30']4-2.00sin. 

 [4«H-286°57']4- .40 sin. 

 [4«<4-288°36']4- .59 sin. 

 [4*<4-281°18']4-1.38sin. 

 [4**4-311° 57']4- .30 sin. 

 [4«*4-305 o 40 / ]4-1.26sin. 

 [4 * <4-310° 52'J4-1.55 sin. 

 [4**4-284° 4']4-1.03 sin. 

 [4 7rH-217°47']4- -98 sin. 

 [4**4-303°55']4-2.90sin. 

 [4**4-312°59']4-2.34sin. 

 [4**4-272°12']4-1.46sin. 

 [4**4-309° 54']+ .58 sin. 

 [4 n *4-333° 25']4- .76 sin. 

 [4 n *+335° 48']4-3.24 sin. 



6 71*4-333° 24' 

 6 7i *+335° 10' 

 6**+ 38° 37' 

 6**4-331° 57' 

 6**4-304° 51' 

 6**+ 51° 19' 

 6**4-300° 55' 

 6**+ 35° 59' 

 6 * *+252° 52' 

 6**4-155° 34' 

 6**4-196° 42' 

 6**4-157° 11' 

 6 * *4-356° 36' 

 6**4-345° 56' 

 6**4-350° 37' 

 6 * *4-189° 28' 

 6**4-180° 9' 

 6 * *4-208° 24' 

 6**4-296° 7' 

 6tt*4- 91° 56' 

 6**4-341° 35' 

 6**+ 73° 20' 

 6**4-305° 17' 

 6**4-131° 6' 

 6 * *4-103° 58' 

 6**4- 71° 35' 

 6**4-185° 44' 

 6**4-241° 41' 

 6**4- 36° 1' 

 7**4-253° 16' 

 6**4-214° 59' 

 6**4- 71° 29' 

 6**4- 30° 48' 

 6**4-345° 52' 

 6 * *4-290° 35' 



Gen.Curve, iV=8.334- 3.03 sin. [2**4-109° 52']+2.53 sin. [4**4-309° 5']+ .16 sin. [6**4-213° 31'] 

 4- .56 sin. [8 * *+162° 45']+ .27 sin. [10 * *4-32o 38']. 



1 This agrees exactly with the formula computed hy Hallstrom. Acta Soc. Sci. Fcnniccr, II. 369. 



