August 21, 19 13] 



NATURE 



649 



In order to record the large declination changes 

 (as high as 12°), a scale value of 225' per mm. had 

 to be employed, while the force ranges required a 

 scale value of 8 to 10 7 per mm. The largest change 

 in force occurred during an auroral storm, when a 

 reduction of more than 1000 y took place in horizontal 

 intensity. 



During the time of occupation a complete and accu- 

 rate log of aurora was compiled. Between March 

 and October, numerous displays were observed, vary- 

 ing from a dull nebulous glow low in the north to 

 splendid designs of arches, curtains, and streamers 

 vividly coloured in green, red, and heliotrope, far 

 surpassing anything seen by Dr. Mawson in McMurdo 

 Sound in 1908. The exact times of prominent phases 

 were noted. A cursory comparison with the mag- 

 netograph records showed a remarkable coincidence 

 of magnetic and auroral storms. The nebulous type 

 of aurora seemed to have little accompanying mag- 

 netic disturbance, but when moving and coloured 

 luminous bands scintillated across the sky, the phases 

 of the accompanying magnetic storm would almost 

 invariably be found to correspond to variations in form 

 or colouring of the aurora. Three splendid displays 

 in the evenings of July 4, 5, and 6 perhaps constituted 

 the most brilliant series. There seemed to be some 

 indication of a recurrence of aurora at definite in- 

 tervals. 



As previously arranged in a scheme of international 

 cooperation, twenty-four special terms of two hours 

 each were "quick run" on the magnetograph. These 

 unfortunately proved wanting in incident, the most 

 disturbed being that of April 16, 1912, when a fairly 

 large movement was recorded. 



From the end of March, 1912, to February 8, 1913, 

 the magnetograph record is almost unbroken. 



In the smaller hut absolute determinations of de- 

 clination, horizontal force, dip, and total force were 

 made once a week. The average values at the station 

 were : — Declination, 6° 30' W. ; horizontal force, 

 003 1 1 C.G.S. ; dip, 87 21-5' S. 



Observations often had to be carried out in winds 

 of eighty to ninety miles an hour, and in a pitchy 

 darkness, since the night hours were the only approxi- 

 mately calm ones magnetically. 



As a check on the absolute hut station, an ice 

 station was occupied during the winter in a cavern 

 dug out of the glacier, half a mile distant. The differ- 

 ence between the two stations was trifling in all the 

 elements. In the early spring Mr. Hannam was in- 

 structed in the conduct of the observatory, and later 

 carried on all work there during the magnetician's 

 absence on sledging journeys. 



In early September, 1912, three reconnaissance par- 

 ties were sent out. One full magnetic station was 

 occupied 11J miles south of winter quarters. 



On account of the persistently furious gales, no 

 start could be made on the long summer sledge 

 journeys until the second week in November. Three 

 main parties then got away, while a fourth was to 

 move off in early December. Of these, one was to 

 make a long journey east, and was provided with a 

 theodolite trough needle for determining magnetic 

 declination ; a second was to explore the more adja- 

 cent eastern coast-line, and besides a three-inch theodo- 

 lite with compass needle, carried a dip circle with 

 two dip needles ; a third party was to make a journey 

 south along either a geographical or a magnetic 

 meridian towards the magnetic pole; while the fourth, 

 carrying a sextant and an improvised declinometer, 

 was to make as far west as possible. All parties were 

 to return not later than January 15, 1913. 



The eastern coastal party, under Mr. C. T. Madi- 

 gan, secured magnetic results at eight stations fairly 

 NO. 2286, VOL. 91] 



distributed over 270 miles. Declinations were obtained 

 with the 2-in. compass needle attached to the theo- 

 dolite, and dips were determined with either one or 

 two needles. 



The third party, t onsisting of Lieut. R. Bage, 

 (leader), J. F. Hurley (photographer), and E. N. 

 Webb (magnetician), left winter quarters, Common- 

 wealth Bay, on November 10, 1912, and was. assisted 

 by a supporting party. A 3-in. Gary theodolite was 

 taken for astronomical observations, and for magnetic 

 observations the dip circle with declinometer and total 

 intensity attachment and four dip needles. Strong 

 head-winds and heavy drift were met with through- 

 out the following week, and, with heavy loads, the 

 travelling, over sastrugi country, was very slow. On 

 November 21, 6;i miles S. by E. from winter 

 quarters, the supporting party left. 



Magnetic observations indicated considerable local 

 disturbance, so to get the advantage of a direct dip 

 gradient to the magnetic pole, the magnetic meridian 

 was followed as nearly as possible. In the course of 

 the outward journey seven full magnetic stations were 

 occupied at intervals of thirty to fifty miles, while, in 

 addition, rough determinations of declination and dip 

 were made at almost every camp. 



The observations at each full magnetic station 

 comprised complete astronomical observations, observa- 

 tions of dip with four needles, double determinations 

 with total force needles, and sixteen settings of the 

 declinometer needle for declination. The declino- 

 meter trough needle proved an excellent instrument, 

 even at the position of highest dip. Nearly all astro- 

 nomical and magnetic observations were computed on 

 the march as obtained. 



For steering purposes on the journey a sun-dial or 

 "shadow compass," computed for the sun's mean 

 declination and equation of time, and the approximate 

 mean latitude, was used. Granted clear weather, this 

 is a verv useful instrument. Steering south-east from 

 the depot, heavy head-winds were met with, the sur- 

 face rising steadily and becoming rougher, with sas- 

 trugi increasing in size. At 100 miles and 174 miles 

 out from winter quarters the party was held up by- 

 severe weather, but occupied itself with magnetic 

 observations. Besides a full magnetic set at the 100 

 miles; a snow shaft 8 ft. deep was excavated, and a 

 temperature gradient obtained, +9 F. at surface to 

 — 13 F. at 8 ft. At 174 miles a continuous observa- 

 tion of declination over twenty-five hours was made 

 with the dip circle trough needle, the party living in 

 a hole dug out of the snow. 



On December 12 a depot of food, oil, &c, was made 

 at 200 miles. With the lighter sledge it was found 

 that runs of from twelve to fifteen miles per day 

 could be made. On December 21 the extreme station, 

 301 miles, was reached, at a height of 5900 ft. above 

 sea-level, in latitude 70 36' S. and longitude 

 148 12' E. At most stations the magnetic meridian 

 for dip observations was obtained by declinometer, 

 but at this station dip was determined with four 

 needles in two directions at right angles, and the 

 meridian and true dip were thence computed; resulting 

 dip, 89 43-3' S. ; declination, 70 49' W. ; total force, 

 06692 C.G.S. Between 200 and 300 miles out the 

 surface was exceedingly rough, sastrugi 5 ft. high 

 from trough to crest being met with. 



Turning back on December 21, the first stages of 

 the return journey were made more rapidly than had 

 been expected, as much of the fresh snow had 

 hardened. A depot which had been laid at 200 miles 

 on the out journey was picked up on December 27, 

 and a full set of magnetic observations taken. During 

 the remaining 200 miles almost continuous overcast 

 weather obtained, making it extremely difficult to pick 



