Part 33 (1/2)
Each day, now, Webb took an approximate magnetic dip and declination in the lee of the break-wind. This was necessary in order to get some idea of local disturbances. Also, it gave us some vague idea as to the direction in which lay the South Magnetic Pole. For instance, at the eighty-three-and-three-quarter-mile camp, the needle showed the Pole to be 18 degrees east of true south, while at our lunch camp that day, six miles farther on, it was given as 50 degrees east of south. The dip was so great that our prismatic compa.s.s would not set closer than about 15 degrees, but the long compa.s.s needle of the dip-circle, though of course sluggish, continued to give excellent results.
Under these conditions it is obvious that the magnetic needle is quite useless for steering purposes. The sun compa.s.s proved itself a more than efficient subst.i.tute. On a snowfield there is usually a total absence of landmarks of any kind, so the direction of wind, sastrugi, or perhaps a low cloud is found with the sun-compa.s.s, frequently checked, and the course kept accordingly. On camping we would generally carefully note the direction in which the sledge was left, in case the next day proved overcast. Thus we would march in the morning by the wind's direction till the sun, gleaming through the clouds for a few moments, enabled us to use the compa.s.s again.
Sastrugi, only six inches high, seen on the 26th, showed the effects of wind-erosion exquisitely. In an individual case the windward end of a sastruga might be completely undercut for six or nine inches, leaving a hard crust, sometimes only one-eighth of an inch in thickness and a couple of inches wide. This would sag downwards under its own weight in a fine curve till the tip rested on the snow beneath. It is marvellous how such a delicate structure can withstand the heavy wind.
November 27 proved a very hard day. The wind kept up sixty miles per hour all the time, so that, after taking four hours to do four and three-quarter miles, we were all thoroughly exhausted. It was not a great run, but the century was hoisted--one hundred and three-quarter miles by sledge-meter; alt.i.tude two thousand nine hundred feet. There was a mild celebration that night over a square of b.u.t.ter-scotch and half an ounce of chocolate, besides the regular hoosh and cocoa.
Next day the light was very bad and the wind fifty miles per hour.
Observations were therefore made inside the tent. Webb, Hurley and the instrument occupied all available s.p.a.ce, while I spent three hours digging a shaft eight feet deep in the snow, taking temperatures every foot. It appeared that the mean annual temperature of the snow was approximately -16 degrees F.
The dip was 88 degrees 54'; certainly rather too large a rise from 88 degrees 20' of twenty miles back. The declination had actually changed about 80 degrees in the last ten miles. This one-hundred-mile station was badly disturbed. From the evidence, it is possible that a subsidiary ”pole” or area of almost vertical dip may exist close by this spot to the west or south-west.
Going straight up wind into a ”blow” which varied from forty to fifty miles per hour, we were able to make eight miles after the previous day's rest. At lunch a hole was dug five feet square and two feet deep.
It served three purposes. First, it gave a good shelter for a longitude observation; secondly, with the mast, yard and floor-cloth we converted it into a shelter snug enough to house the primus and to lunch comfortably; and thirdly, a mound was left as a back-mark which was picked up on the return journey.
By experience we found that a warm lunch and a rest enabled one to ”peg”
along a good deal farther than would otherwise be possible.
The ”scenery” in the afternoon became if possible more desolate--very few new sastrugi, the surface appearing generally old and pitted. In some places it was rotten and blown away, disclosing coa.r.s.e granulated substrata. At the top of one ridge the snow merged into neve split into small creva.s.ses, nine inches wide and four or five yards apart. The camp was pitched, here, at 11 P.M. The lat.i.tude was 68 degrees 32' S., and we saw the midnight sun for the first time that summer, about one-quarter of its rim remaining above the horizon.
A full hurricane came up and kept between fifty and sixty miles per hour all day on the 30th. Before moving off, Webb found that the magnetic needle had ”waltzed” back 60 degrees since the one-hundred-mile camp, now pointing 80 degrees east of south. Still, to allow the needle to makeup its mind, we steered into the wind at 2 P.M., losing the neve and meeting very rough country. By 6 P.M., with four miles to our credit, we were nearly played out. It was being discussed whether we should go on when the discovery was made that the theodolite legs were missing; probably having slipped out in one of the numerous capsizes of the sledge.
The solemn rites of ”shut-eye” determined that Webb was to stay and make camp while Hurley and I retraced our steps. It was no easy matter to follow the trail, for on hard snow the sledge runners leave no mark, and we had to watch for the holes of the crampon-spikes. About two and a half miles back, the legs were found, and there only remained a hard ”plug” against the wind to camp and hoosh.
While we were lying half-toggled into the sleeping-bags, writing our diaries, Hurley spent some time alternately imprecating the wind and invoking it for a calm next day. As he said, once behind a break-wind one could safely defy it, but on the march one is much more humble.
Whether it was in honour of Queen Alexandra's birthday, or whether Hurley's pious efforts of the evening before had taken effect, December 1 turned out a good day. By noon, the wind had dropped sufficiently for us to hoist the Jack and Commonwealth Ensign for the occasion.
After four miles of battling, there came into sight a distinct ridge, ten miles to the west and south--quite the most definitely rising ground observed since leaving the coast. In one place was a patch of immense creva.s.ses, easily visible to the naked eye; in another, due south, were black shadows, and towards these the course was pointed.
At a point more than one hundred and twenty-five miles from the sea, a skua gull paid an afternoon call, alighting a few yards from the track.
I immediately commenced to stalk it with a fis.h.i.+ng-line, this time all ready and baited with pemmican. However, it was quite contemptuous, flying off to the south-south-east as far as we could follow it. Was it taking a short cut to the Ross Sea?
December 2 saw us through ”Dead-Beat Gully” to a rise, in sight of the shadows towards which we had been steering. Two miles away they appeared like the edge of the moon seen through a large telescope. The shadows were due to large mounds of snow on the south side of a steep escarpment. Three main prominences were cross-connected with regular lines of hillocks, giving the impression of a subdivided town-site. The low evening sun threw everything up in the most wonderful relief.
On the morning of the 3rd we were in a valley running west-north-west and east-south-east. The southern side rose steeply and from it projected three large mounds, about two hundred feet from the bottom of the valley, into which they fell just like tailings-heaps from a mine.
They were christened ”The Nodules.”
Going due south uphill over neve we found ourselves in a regular network of creva.s.ses. They were about ten feet wide and well bridged. Most noticeable were ”hedges” of ice up to six feet in height on either side of the creva.s.ses which ran southward. It was now nearly calm and in every crack and c.h.i.n.k in the snow-bridges beautiful fern-like ice-crystals were seen. These must have been just forming, as a very light puff of wind was seen to destroy many of them.
We spent three hours exploring the locality. On nearing the top of the ridge, roped together, we found that the creva.s.ses were becoming much wider, while the ”hedges” were disappearing. The centre ”nodule” was found to be immediately north or to the leeward of the intersection of two creva.s.ses, each about forty feet wide. The bridge of one creva.s.se had dropped some thirty feet for a length of eighty yards. Doubtless, an eddy from this hole accounts for the deposit of snow and, by accretions, for the erection of the nodule. Webb went down at the end of the alpine rope and found the bridge below quite solid.
For about half a mile the summit of the slope was practically level, three hundred feet above the bed of the valley. The surface was still of neve, intersected by ca.n.a.ls forty, sixty and eighty feet wide, in which the snow-bridge was generally four or five feet from the brink.
On the south-west horizon, perhaps twenty miles away, was a salient crest streaked by three dark vertical bars; evidently another creva.s.sed area.
Returning to the sledge, we toggled-on and worked it up over the top of the ridge, much regretting that time would not allow us to examine the other two large ”nodules.” Hurley was in the lead, lengthening his line by thirty feet of alpine rope, but even then all three of us and the sledge were often on the lid of a creva.s.se. Luckily, the lids were fairly sound, and none of us went in beyond the waist. Finally, the trail emerged on to ordinary sastrugi once more, where a halt was made for lunch. We were all glad to have seen the place, but I think none of us has any wish to see another like it.
That night, after following the magnetic needle towards the south-east, we were fairly on the plateau at one hundred and forty miles, with an alt.i.tude of four thousand four hundred feet. The dip, however, had steadily decreased, standing now at 88 degrees 30'. There was some consolation in the hope that a big, sudden rise was stored up for us somewhere along the way ahead.
December 4 and 5 were fine days, giving only twenty-two miles, as we met with a rough surface; a large quant.i.ty of very hard, razor-backed sastrugi, generally about two feet high, like groined vaulting inverted, on a small scale. Sledge and sledge-meter both had a very rough pa.s.sage.