264 COMPARISON OF ARCTIC AND ANTARCTIC DISTURBANCES. 



was apparently larger, but owing to its rapidity the trace is too faint to follow to the turning-point. 

 Simultaneously there was a very sudden rise of 20y in V, which was preceded and followed by slower 

 movements in the opposite direction. On examining Plate X one observes a small sudden movement at 

 least approximately synchronous with these Antarctic movements at Matotchldn Schar, Dyrafjord, and 

 the American stations, but it cannot be identified with certainty in the Kew curves. There was no record 

 obtained in the Antarctic from 23h. 56m. on the 14th until Oh. 19m. on the 15th. After the latter 

 hour, however, there was a deep bay on the D curve, the element rising 99' between Oh. 33m. and 

 Ih. llm., and falling 106' between Ih. llm. and 2h. 12m. H rose 48y between Oh. 53m. and Ih. 23m. ; 

 the trace then went off the sheet on the positive side, remaining off until 2h. 33m. After coming on 

 for a few minutes, it was again off until 3h. V rose 65y between Oh. 47m. and Ih. 23m., and then 

 fell 36y between Ih. 23m. and 2h. 8m. 



These movements, it will be observed, occur about the time of the principal movements in BIEKELAND'S 

 Arctic stations. On their conclusion the Antarctic curves were relatively quiet during the next 12 hours. 



20. December 24-25, 1902 (hours 23-5, Plate XI). 



This disturbance is included amongst the " compound." In temperate Europe BIRKELAND says, p. 165, 

 " the conditions are slightly disturbed from 23h. on the 24th to 5h. on the 25th. There are especially 

 distinct perturbations about midnight, and from 2h. 30m. to 4h." In Toronto and at Baldwin and 

 Cheltenham, U.S., the perturbation is practically confined, BIRKELAND says, to the short interval 3h. 14m. 

 to 3h. 57m. on the 25th, with maximum at 3h. 21m. At Dehra Dun, Batavia, and Christchurch 3h. to 

 4h. is also decidedly the most disturbed time. The Arctic stations are as much disturbed between 23h. on 

 the 24th and Oh. 15m. on the 25th as they were later, while temperate European stations are also sensibly 

 disturbed at the earlier hour. BIRKELAND concludes, p. 165, that in Europe, as a whole, the conditions 

 " are in the main connected with the polar storms at the Norwegian (i.e. Arctic) stations." 



The disturbance at the non-polar European and Asiatic stations was really very trifling. At Kew the 

 only changes in D at all conspicuous were a rise of l'-2 between 23h. 5m. and 23h. 18m., followed by 

 a fall of l' - 6 between 23h. 24m. and 23h. 35m. on the 24th, and a rise of 2' - 6 between 3h. 14m. and 

 3h. 21m., followed by a fall of 2' ending about 4h. 5m. on the 25th. In H there was a rise of 9y between 

 3h. 34m. and 3h. 55m. on the 25th. The other changes hardly catch the eye. 



In the Antarctic it was rather quieter than usual for 2 or 3 hours prior to 23h. on the 24th. 

 There then ensued a decidedly more disturbed time, extending from about 23h. 15m. on the 24th to 

 Oh. 13m. on the 25th. Between 23h. 15m. and 23h. 54m. D rose 28', fell 84' and rose 57'. H, during 

 this time, had a total range of only 45y, but there was rather a prominent double oscillation composed of 

 a rise of 38y in 4 minutes, a fall of 45y in 6 minutes, a rise of 42y in 9 minutes, and a fall of 24y in 

 8 minutes. Between 23h. 19m. and 23h. 56m. V fell 40y and rose 53y. Owing to the trace coming on 

 the clamp, there was no Antarctic record from Oh. 18m. until the new sheet was put on at Oh. 55m. on the 

 25th. Conditions were distinctly quiet for over an hour after this. The H trace was off the sheet on the 

 positive side from 2h. 23m. to 4h. 48m., so there may have been high values in that element. Between 

 2h. 15m. and 4h. 19m. D fell gradually 130', but a very appreciable fraction of this must be ascribed to the 

 regular diurnal variation. The fall was interrupted as usual by a good many minor oscillations, the 

 largest retrograde movement being a rise of 26' between 3h. 12m. and 3h. 21m. The V trace showed 

 no large oscillations, but there were a number of minor oscillations between 3h. 20m. and 4h. 35m. 



The Antarctic movements are synchronous with and larger than those seen at the American and 

 non-polar European stations. 



The reader should, however, be warned that one would not naturally regard any portion of the time 

 covered by Plate XI as more than usually disturbed in the Antarctic, with the exception of the last hour 

 of the 24th. At the same time, the end of Plate XI answers to the early afternoon in the Antarctic, and 

 the diurnal changes at Midsummer were then so rapid that irregular disturbances appeal less to the eye 

 than at most hours of the day. 



21. December 26-27, 1902 (hours 18-2, Plate XII). 



This is included amongst the "polar elementary" storms. From the discussion on p. 137 we learn that 

 it comprised two distinct " elementary" storms, the first especially powerful at Matotchkin Schar, having 



