eight marches as against ten, showing the first slight slackening as P.O. Evans and Oates began to feel the cold; from Upper Glacier to Lower Glacier Depôt ten marches as against eleven, a stage broken by the Mid-Glacier Depôt of three and a half days' provisions at the sixth march. Here there was little gain, partly owing to the conditions, but more to Evans' gradual collapse.
The worst time came on the Barrier; from Lower Glacier to Southern Barrier Depôt (51 miles), 6½ marches as against 5 (two of which were short marches, so that the 5 might count as an easy 4 in point of distance); from Southern Barrier to Mid Barrier Depôt (82 miles), 6½ marches as against 5½; from Mid Barrier to Mt. Hooper (70 miles), 8 as against 4¾, while the last remaining 8 marches represent but 4 on the outward journey. (See table on next page.)
As to the cause of the shortage, the tins of oil at the depôts had been exposed to extreme conditions of heat and cold. The oil was specially volatile, and 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 escape through the stoppers even without damage to the tins. This process was much accelerated by reason that the leather washers about the stoppers had perished in the great cold. Dr. Atkinson gives two striking examples of this.
1. Eight one-gallon tins in a wooden case, intended for a depôt at Cape Crozier, had been put out in September 1911. They were snowed up; and when examined in December 1912 showed three tins full, three empty, one a third full, and one two-thirds full.
2. When the search party reached One Ton Camp in November 1912 they found that some of the food, stacked in a canvas 'tank' at the foot of the cairn, was quite oily from the spontaneous leakage of the tins seven feet above it on the top of the cairn.
The tins at the depôts awaiting the Southern Party had of course been opened and the due amount to be taken measured out by the supporting parties on their way back. However carefully re-stoppered, they were still liable to the unexpected evaporation and leakage already described. Hence, without any manner of doubt, the shortage which struck the Southern Party so hard.
Note 27, p. 594.—The Fatal Blizzard. Mr. Frank Wild, who led one wing of Dr. Mawson's Expedition on the northern coast of the Antarctic continent, Queen Mary's Land, many miles to the west of the Ross Sea, writes that 'from March 21 for a period of nine days we were kept in camp by the same blizzard which proved fatal to Scott and his gallant companions' (Times, June 2, 1913). Blizzards, however, are so local that even when, as in this case, two are nearly contemporaneous, it is not safe to conclude that they are part of the same current of air.
