August 21, 1913] 



NATURE 



051 



were obtained by aneroids, standardised by a hypso- 

 meter. 



The only life seen consisted of two snow petrels at 

 eighty miles, and a skua gull at 125 miles, while no 

 sign of rock was seen. 



Longitude observations at three stations on the 

 outward march were repeated on the return, so that 

 the chronometer rate over three sections could be 

 determined, giving good final longitudes. 



Between 100 and 200 miles strong magnetic disturb- 

 ance was evident. Declination chopped round by 90 

 in as short a distance as ten miles, while reversion 

 of dip gradient was very commonly experienced. From 

 200 to 300 miles the declination was much more con- 

 stant, and a steady dip gradient was observed. Con- 

 tinuing this last fair gradient, the 300-mile station was 

 probablv about forty miles from a position of maximum 

 dip. 



At the extreme western base 200 miles east of 

 Gaussberg, and 1100 odd miles distant from the main 

 base, magnetic conditions were better, but weather 

 conditions were harassing. No magnetographs were 

 provided, but periodic absolute observations were to 

 be taken by the magnetic observer, Mr. A. L. Ken- 

 nedy. Observations with magnetometer and dip 

 circle were taken when possible. The station was 

 situated on a floating glacier or barrier, and during 

 the year determinations of the azimuth of the mark 

 showed a progressive movement. During the sledge 

 journeys — as far as Gaussberg in the west, and for 150 

 miles to the east — declinations were obtained at in- 

 tervals with a prismatic compass, or with a declino- 

 meter attachment to a Lloyd-Creak dip circle. Two 

 sets of dip were obtained on the eastern journey. 



Term days were kept at the western base when 

 possible by continuous eye readings of declination, 

 while aurora? were observed and several observations 

 of declination taken during active auroral disturbance. 

 The accompanying plan shows most of the declina- 

 tions and dips obtained. The possibilities of highly- 

 disturbed areas are illustrated by the anomalous de- 

 cimations and dips about 100 to 174 miles. At 132 

 miles heavy crevasses were found, which seemed to 

 indicate some unconformitv beneath the ice-sheet. 



Notes by Prof. Edgeworth David. 



I have only just received by wireless some of the 

 actual dips obtained by Dr. Mawson with a Lloyd- 

 Creak dip circle other than those already published 

 in Shackleton's work, "The Heart of the Antarctic." 



First, at the Nordenskjold ice-barrier, lat. 76° 14' S-, 

 long. 163 9' E., the dip was found to be 88i° S. ; 

 at the Drvgalski Ice Barrier Tongue, in lat. 75 28' S., 

 long. 163 15' E., the dip was S75 . On the Reeves 

 Glacier, in lat. 74 48' S., long. 161 30' E., it was 

 87-9°. All these three sets of observations were very 

 carefully taken. Again at lat. 73 S., long. 156 10' E., 

 a careful set of observations showed the dip to be 

 89 10'. The next observation, which may not be 

 looked upon as quite so accurate as the others,, gave 

 the dip as 89 45', in lat. 72 42' S., long. 155° 40' E., 

 and the last observations, also of approximate accuracy 

 only, indicated a dip of 89 48', at a spot thirteen miles 

 to S. 30 E. of our furthest point to N.W., the latter 

 being; in ' at . 72 25' S., long. 155 16' E. 



When we reached the spot where we recorded a dip 

 of 89 45', on January 15, 1909, Mawson concluded 

 that as the rate of change of dip had con- 

 siderably increased in the last twenty-five miles 

 we were close to the edge of the area of 

 the vertical needle. The evening of the same 

 day, when seven miles nearer the south magnetic 

 pole area, Mawson 's measurements gave the dip as 

 89 48'. On striking a curve, he estimated that the 



NO. 2286, VOL. 91] 



actual edge of the region of verticity was only about 

 thirteen miles distant from where our dip of S9 48' 

 was recorded. We had already travelled twenty-seven 

 miles beyond the spot where the results of the Dis- 

 covery observations had placed the south magnetic pole 

 during 1902-3. Accordingly we determined to march 

 on thirteen miles and put up the flag there, as being 

 the edge of the area of the vertical needle. Our pro- 

 ceedings have already been described in vol. ii., "The 

 Heart of the Antarctic," pp. 180-2. During these last 

 thirteen miles we took no observations with the dip 

 circle, the tripod of which we utilised as a mark to 

 guide us back on our return march. 



Mawson estimated that the position of our furthest 

 point to the north-west was in lat. 72 25' S., long. 

 155 16' E. A short distance on our return from the 

 spot considered to be the edge of the area of vertical 

 needle, Mawson experimented with the horizontal 

 needles of an ordinary prismatic compass and a Brun- 

 ton transit instrument. While he considered both 

 needles worked "dead" — that is to say if the compass 

 boxes were twisted the needles followed them around — 

 it was found that on tapping the boxes and making 

 the needles spin, the more sensitive of the two showed 

 a slight tendency for its south-seeking end to come 

 to rest within the western hemisphere of the compass. 

 Mawson felt satisfied at the time that even if we might 

 not have been within the area of vertical needle, at 

 the particular moment — about 3.30 p.m., on January 

 16, 1909 — when the end of our journey was reached, 

 we were still well within the region of the diurnal 

 swing of that area. In view, however, of the recent 

 remarkable observations by Mr. E. N. Webb, it seems 

 doubtful whether there may not have been some local 

 disturbing- influences affect'ing Mawson 's observations 

 on the Shackleton expedition, such as Webb's map 

 shows affected the magnetic observations of Maw- 

 son's present Antarctic expedition. Reference to the 

 map will show that at several spots along their routo 

 declination varies to the amount of from 40° up to 

 69 within a distance of only a few miles, and the 

 dip, in some places, lessened considerably, instead 

 of increasing, as the magnetic polar area was 

 approached. 'This suggests that it is possible that at 

 our furthest point north-west we may have been on 

 the edge of either a local pole, an "outlier" of the 

 main south magnetic polar area, or on a local lobe of 

 the magnetic pole area, or may even have been just 

 outside an area of absolute verticity altogether. By 

 how much, if at all, we may have been outside, can, 

 of course, only be determined when all the magnetic 

 results are reduced, and compared. 



ME ROE: FOUR YEARS' EXCAVATIONS OF 

 THE ANCIENT ETHIOPIAN CAPITAL. 1 



ON behalf of the University of Liverpool, and aided 

 by the support of private benefactors, the lec- 

 turer has been at work for four years in scientifically 

 uncovering the ruins of the once-famous Ethiopian 

 capital. When his first expedition arrived upon the 

 scent, there was little to suggest the great extent and 

 interest of the city which has now come to light ; in 

 fact, onlv one wall and a few objects of sculpture 

 were visible above the soil. Now, however, a number 

 of temples, palaces, and public buildings have been 

 laid bare ; the walls of the royal city have been traced ; 

 and during the past season's work, from which the 

 lecturer has just returned, a considerable portion of 

 this enclosure has been excavated so that a visitor 

 may enter bv the city gate and walk along the ancient 



1 Summary of a discourse delivered at the Roya! Institution on Friday, 

 April 25, by Prof. John Garstang. 



