266 COMPARISON OF ARCTIC AND ANTARCTIC DISTURBANCES. 



For some time after 23h. 50m. on the 26th, when the next sheet was put on, there were some fair 

 movements, notably some rapid nearly synchronous oscillations in the traces of the three elements between 

 Oh. 20m. and Ih. Om. on the 27th. After this the conditions became distinctly quieter. 



The temperature trace was lacking or imperfectly visible during most of the time, and the V changes 

 recorded for times prior to 21h. 30m. are not corrected for temperature. The oscillations were, however, 

 so rapid that the uncertainty thus arising is small. 

 22. December 28, 1902 (hours 3-8, Plate XIII). 



This date was not given in Prof. BIHKEI.AND'S circular, and he had few data for it from nun polar 

 regions except from America. He has classified the storm, p. 169, as "compound," though the phenomena 

 at Dyrafjord, where it was largest, suggested a " polar elementary " storm, whose centre was originally 

 somewhere to the south of Greenland, and which moved to the westward. The classification seems to 

 have been partly determined by the fact that the time of the chief disturbance from 4h. 40m. to 6h. 

 was an unusual one for the occurrence of " elementary polar " storms. 



The curves reproduced from the European co-operating stations include only D and H from San 

 Fernando and D from Stonyhurst. The Kew D curves between 4h. 30m. and 6h. 30m. showed two wave- 

 like movements; in each a rise of about l' - 5 was followed by a more gradual fall, the crests coming at 

 about 4h. 50m. and 6h. Om. The H curve also showed two waves, H falling about 6y between 4h. 30m. 

 and 4h. 50m., and rising 7y between 4h. 50m. and 5h. 15m., then falling 5y between 5h. 15m. and 5h. 30m., 

 and rising very slowly about 5y to a maximum near 6h. 20m. 



There was a somewhat larger disturbance at Kew about midnight on the 27th, but it precedes the time 

 covered by Plate XIII. The movements lasted from about 21h. on the 27th to Oh. 30m. on the 28th. 



In the Antarctic the most notable phenomenon was a deep bay on the D trace, of the same character as 

 appeared during the " special type" of disturbance. The element began to fall suddenly about 5h. 13m. 

 and in 13 minutes fell 90', going off the sheet on the negative side and remaining off for 11 minutes. 

 During the next 12 minutes it was off and on the sheet once or twice, and then continued to rise with 

 minor oscillations. The rise was not so rapid as the fall, and owing to the minor oscillations it is difficult 

 to assign a definite time for the conclusion. D had, however, returned to its original value by about 6h. 20m. 

 H was off the sheet on the positive side from 3h. 35m. to 6h. 25m., and so far as that element was 

 concerned the disturbance might have been of the " special type." The V trace, however, was not of that 

 type. There was a rapid fall of 18y between 5h. 14m. and 5h. 19m., followed by a rise of 29y between 

 5h. 19m. and 5h. 37m. But during the rise there were numerous small oscillations which continued until 

 6h. 20m. 



The Antarctic curves, it may be added, were somewhat highly disturbed on the 27th, from 16h. 15m. 

 until 23h. 55m., when the sheet was taken off. 

 23. January 26, 1903 (hours 7-15, Plate XIV). 

 During this time the Antarctic magnetographs were not in action. 

 24. January 26-27, 1903 (hours 18-7, Plate XV). 



This " compound " storm appears in Europe outside the Arctic as " a long perturbation . . . lasting 

 from about 18h. Om. on the 26th ... to 7h. Om. on the 27th . . . We have . . . three . . . sharply 

 defined intermediate storms," p. 287. These " intermediate " storms are said to coincide, on the whole, in 

 time with three storms recorded in the Arctic, especially powerful at Axeloen. 



The last, however, of these three " intermediate " storms attained its maximum about Oh. 35m. on the 

 27th, and the Antarctic records do not commence until Ih. 5m. By this time there was comparatively 

 little disturbance except in the Arctic, and even there it was much reduced. 



In the Antarctic after Ih. 5m. there was a fall in progress in D until 4h. 8m., when the curve got off 

 the sheet for a few minutes. A fall is what we should expect in the ordinary course of events, but the 

 fall shown between the hours mentioned, 198', is notably in excess of the average. The fall in D was 

 interrupted as usual by minor oscillations. The most conspicuous of the retrograde movements, one of 

 57', took place between 2h. 23m. and 2h. 46m. The D trace was off the sheet between 5h. 25m. and 

 6h. Om., and the form of the curve when going off and coming on is not inconsistent with the existence of 

 a bay of considerable depth. 



