Magnetic Observations at Cambridge, United States. 135 
EXTRA OBSERVATIONS. 
It has been the custom at the Cambridge Observatory, as elsewhere, to observe, at the 
shortest possible intervals, the magnetic elements, whenever symptoms of any great mag- 
netic disturbance were discovered, or the presence of an Aurora made it probable that the 
Magnetometers would be unusually deranged. The following results of the extra obser- 
vations made at these irregular periods may be of some value in determining how far such 
magnetic storms extend, what are their laws, and what, if any, is their connection with the 
Aurora. At such periods the observer has generally marked the extreme limit of every 
vibration of the Magnetometer, and noted the time as often and as accurately as practicable. 
Gottingen | Gottingen Gottingen Gottingen ), Gottingen Gottingen | 
Mean Dec. Mean Dec. Mean Dec. Mean Dec. Mean Dec. {| Mean Dec. 
Time. Time, Time. Time. | Time, | Tune. 
Nov. 18,1841. |jh. ms, ee 1 ee) heim, 28; jh. m. 8. ho om 8, 
h. m. 8.| 12 43 0/1200 |/15 51 351670] 16 15 35]120.0? 16 33 40) 460 ]18 36 0)105.0 | 
11 13 0138 .0')/12 48 30)118 2 |]15 51 55 1550116 15 50}124.0 |16 34 0) 63.0 118 36 15 1020) 
IL 22 0 122.0 |/12 49 O/112.2 |}15 52 30 150.0 | 16 16 0118.0 |16 34 20) 43.0 [18 37 20/107.0 
11 25 0138 02/12 49 30/111 5 |}115 52 45 1590 | 16 17 30]137.0 |16 34 45) 680 1/18 37 40 108.0 | 
11 30 0 171.03) 12 49 45/110.7 |]15 53° 0,148.0} 16 17 35/124.0 116 35 0) 43.0} 18 38 0)106.0) 
11 35 01550 |/12 50 0/112.0 |]15 53 15,151.0 | 16 17 55]/140.0 |16 35 30) 54.0] 18 33 23)110.0 
11 40 0150.0 12 50 30/111.0 |115 53 33 137.0 |:16 18 35/133 0 |16 35 55) 75.0 |)18 38 37/108.0 
11 45 0 140.0 //12 51 01123 1/115 54 0140.0} 16 19 21/1150 [16 36 10) 59.04) 18 39 30)112.0 
54 25123.0}16 20 0} 97.0 |16 36 23) 790 118 39 55)114.0 
11 50) 01370 |}12 5L 80/113 6 [15 } 
11.55 0 156.0 ]/12 52 0/1152 ]}15 55 0111 0}16 20 15/107.0 |16 36 42, 57.09)|18 40 32) 112.0 
12 7 01430 ]/12 52 30/1 16.3 |]15 55 27)106.0 | 16 20 30) 73 09 |16 37 0, 770 18 41 OjtIL.O| 
12.10 0 147.0 |)12 53) 0117.2 15 55 45} 90.0} 16 20 50} 86.0 |16 37 20, 65.0 }18 41 20/114.0 
12 27 0 137.3 |/12 53 30)118.8 115 56 15) 790}16 2L 5) 70.0 16 33 0) 65.0 {/18 41 50/112.0 
12 32 30.1388 }/12 54 0/121.0 |/15 56 30) 90.0 | 16 21 25) 850 |16 38 10) 77 08/18 42 O/114.0 
137.0 ||12 54 30/1225 80.0 ||)16 21 45) 62.0 640 |/18 42 32)117.0 
12 34 0135.0 |12 55 0126.1 |]15 57 0} 86.0 |/16 22 15) 57.0 72.0 ||18 42 47/115.0 
12.35 0135.0 ||12 55 30/1300 ||15 57 30] 75.0 |/L6 22 32) 69.0 620 18 43 151150 
12 36 0,137.0 12 56 0)134.0 1115 57 45) 820 ||16 22 50 50.0 77.0 ||18 43 35/116.5 
12 36 10 138.0 |)12 56 30)135.5 |}15 58 0) 70.0 |/16 23 11) 64.0 |16 39 45) 68.0 |/18 43 50/116.0 
12 37. 0,139.8 |.12 57 0)139 0 }]/15 58 15} 83.0 ||16 23 27! 45.0 |16 40 0) 77.0 |/18 44 10)119.0 | 
12 37 30/141.5 | 12 57 30/140.7 |/15 58 32) 73.0 |/16 23 50) 630 |16 40 40) 82.06/18 44 30'118.0 
12 38 0139.5 |/12 58 0/143.0 |115 58 50) 85.0 |/16 24 10) 53.0 16 42 32 101.0 |/18 44 50/120.0 
12 38 30/138. |/12 58 30/1458 |/15 59 0] 78.0 |/16 24 27) 63.0 ||16 43 0109.0 |/18 45 21)123.0 | 
12 39 0/136.5/12 59 0/147.2 ||15 59 30] 89.0 ||16 24 40) 76.0 ||16 43 30 116.0 ||18 45 40)121.0) 
12 39 30/134.3 | 12 59 30/1505 ]16 0 (| 94.0 //16 25 10) 47.0 | 18 30 15] 95.0 ||/18 46 10)124.0 
12 40 0/134.3]/13 0 0/1522 )/16 0 30) 97.0716 25 45} 37.0 |,18 30 26/100.0 |]18 46 30/125.0 | 
12 40 30)134.6/13 3 01540116 1 0/1050 |/16 26 0) 400 }/18 30 44) 93.0 /|18 47 0/1260) 
12.41 0/1354//13 4 0/156.2]116 1 30} 970 ||/16 26 30) 25.0 ||18 31 0} 98.0 ]/18 48 0127.0 
12 41 30)1362/14 0 0, 4 1 37/107.08)/16 26 40) 41.0 18 31 20) 94.0 |}18 48 30/128 0 
12 42 0/137.0/15 46 | > 16 2 0/1000 |)16 27 0) 180 })18 31 39) 98.0 18 49 15]127.0 
12 42 30)1380}15 47 30)151.0 116 2 15)111.09/16 27 15) 21.0 ]18 32 0} 94.0 |/18 50 20)129.0 
12 43 0/1389]15 48 0/153.08//16 2 30/1040 |116 27 33] 8.0 ||18 32 19] 98.0 }/18 52 20/130.0 
2 
3 
3 
3 
4 
4 
4 
5 
12 43 30/140.0 |\15 48 30/158.0 |/16 50/114.0 116 23 0) 6.0 |/18 32 40} 95.0 }/18 54 0/1300 
12 44 0139.6 ||15 49 O}151.0 |/16 5,107.0 ||16 23 50) 19.0 ||18 32 55) 97.0 |}18 54 20/129.0 
12 44 30)138.9 |/15 49 20/158.0 {|16 5}115.0 |/16 30 0) 40.0 ||18 33 21) 99.0 }}18 54 40)128.0 
12 45 0/138.0 [115 49 30/143.0 ||16 45}109.0 |}16 3L 0) 50.0 |/18 33 43] 97.0 ||18 55 5)127.0 
12 45 30)137.2 }115 49 45)165.0 }|16 Oj116.04}16 3L 15) 44.0 })18 34 0} 99.0 }}/18 55 30)/123.0 
12 46 0/1355 |\15 50 10/155.0 |/16 ( 
12 46 30)133.2 }|15 50 30/168.0 ||16 5]113.0 |}16 32 15) 54.0 |/18 35 0} 100.0 
12.47 0)1290 15 51 21169.0 116 0}118.0 |}16 33 0) 570).18 35 22)103.0 
{12 47 30/122.0 15 51 Q0161.0 116 15 27/125.0 116 33 30) 44.0 [118 35 40'101.0 | 
1 Bright shoots, 2 Arch forms. 3 Disappears. 4 Brighturch. 5 Beautiful aboots. 6 Aurora shoots up brightly, 
7 Aurora fades. 8 Shoots up again. 9 Ceases. 1 Merry dancers. Colored. 3 Merry dancers up to zenith. 
4 Fades. 5 Dances. 6 Still dances, 
118.0 |]16 31 43) 58.0 ])/18 34 30/101.0 
