The return journey on the summit was made at good speed, for the party accomplished in 21 days what had taken them 27 days on the outward journey. But the last part of it, from Three Degree to Upper Glacier Depôt, took nearly eight marches as against ten, and here can be seen the first slight slackening as P.O. Evans and Oates began to feel the cold. From the Upper Glacier to the Lower Glacier Depôt there was little gain on the outward journey, partly owing to the conditions but more to Evans' gradual collapse. And from that time onward the marches of the weary but heroic travelers became shorter and shorter.
As regards the cause of the shortage of oil, the tins at the depôts had been exposed to extreme conditions of heat and cold. The oil in the warmth of the sun—for the tins were regularly set in an accessible place on the top of the cairns—tended to become vapour and to escape through the stoppers without damage to the tins. This process was much hastened owing to the leather washers about the stoppers having perished in the great cold.
The tins awaiting the Southern party at the depôts had, of course, been opened, so that the supporting parties on their way back could take their due amount. But however carefully the tins were re-stoppered, they were still liable to the unexpected evaporation and leakage, and hence, without the smallest doubt, arose the shortage which was such a desperate blow to Scott and his party.]
Apart from the storage of fuel everything was found in order at the depôt, and with ten full days' provisions from the night of the 24th they had less than 70 miles between them and the Mid-Barrier depôt. At lunch-time Scott wrote in a more hopeful tone, 'It is an immense relief to have picked up this depôt, and, for the time, anxieties are thrust aside,' but at night, after pulling on a dreadful surface and only gaining four miles, he added, 'It really will be a bad business if we are to have this plodding all through. I don't know what to think, but the rapid closing of the season is ominous.... It is a race between the season and hard conditions and our fitness and good food.'
Their prospects, however, became a little brighter during the following day, when the whole march yielded 11.4 miles, 'The first double figures of steady dragging for a long time.' But what they wanted and what would not come was a wind to help them on their way. Nevertheless, although the assistance they so sorely needed was still lacking, they gained another 11-1/2 miles on their next march, and were within 43 miles of their next depôt. Writing from 'R. 40. Temp. -21°' on Monday night, February 26, Scott said, 'Wonderfully fine weather but cold, very cold. Nothing dries and we get our feet cold too often. We want more food yet, and especially more fat. Fuel is woefully short. We can scarcely hope to get a better surface at this season, but I wish we could have some help from the wind, though it might shake us up badly if the temp. didn't rise.'
Tuesday brought them within 31 miles of their depôt, but hunger was attacking them fiercely, and they could talk of little else except food and of when and where they might possibly meet the dogs. 'It is a critical position. We may find ourselves in safety at next depôt, but there is a horrid element of doubt.'
On the next day Scott decided to increase the rations, and at R. 42, which they reached after a march of 11-1/2 miles in a blightingly cold wind, they had a 'splendid pony hoosh.' The temperatures, however, which varied at this time between -30° and -42°, were chilling them through and through, and to get their foot-gear on in the mornings was both a painful and a long task. 'Frightfully cold starting,' Scott wrote at lunch-time on Thursday, February 29, 'luckily Bowers and Oates in their last new finnesko; keeping my old ones for the present.... Next camp is our depôt and it is exactly 13 miles. It ought not to take more than 1-1/2 days; we pray for another fine one. The oil will just about spin out in that event, and we arrive a clear day's food in hand.'
On reaching the Middle Barrier Depôt, however, blow followed blow in such quick succession that hope of pulling through began to sink in spite of all their cheerfulness and courage. First they found such a shortage of oil that with the most rigid economy it could scarcely carry them on to their next depôt, 71 miles away. Then Oates disclosed the fact that his feet, evidently frost-bitten by the recent low temperatures, were very bad indeed. And lastly the wind, which at first they had greeted with some joy, brought dark overcast weather. During the Friday night the temperature fell to below -40°, and on the next morning an hour and a half was spent before they could get on their foot-gear. 'Then on an appalling surface they lost both cairns and tracks, and at lunch Scott had to admit that they were 'in a very queer street since there is no doubt we cannot do the extra marches and feel the cold horribly.'
Afterwards they managed to pick up the track again, and with a march of nearly 10 miles for the day prospects brightened a little; but on the next morning they had to labour upon a surface that was coated with a thin layer of woolly crystals, which were too firmly fixed to be removed by the wind and caused impossible friction to the runners of the sledge. 'God help us,' Scott wrote at mid-day, 'we can't keep up this pulling, that is certain. Amongst ourselves we are unendingly cheerful, but what each man feels in his heart I can only guess. Putting on foot-gear in the morning is getting slower and slower, therefore every day more dangerous.'
No relief whatever to the critical situation came on Monday, March 4, and there was in fact little left to hope for except a strong drying wind, which at that time of the year was not likely to come. At mid-day they were about 42 miles from the next depôt and had a week's food; but in spite of the utmost economy their oil could only last three or four days, and to pull as they were doing and be short of food at the same time was an absolute impossibility. For the time being the temperature had risen to -20°, but Scott was sure that this small improvement was only temporary and feared that Oates, at any rate, was in no state to weather more severe cold than they were enduring. And hanging over all the other misfortunes was the constant fear that if they did get to the next depôt they might find the same shortage of oil. 'I don't know what I should do if Wilson and Bowers weren't so determinedly cheerful over things.'