Thus ice mounds, somewhat similar in shape to the sinter mounds formed by the geysers of New Zealand, Iceland and Yellowstone Park, are built up round the orifices of the fumaroles of Erebus.
Next morning when the party got up at 4 A.M. they had a splendid view of the shadow of Erebus projected on the field of cumulus cloud below them by the rising sun, and while Marshall was attending to Brocklehurst, the hypsometer, which had become frozen on the way up, was thawed out, and a determination of the boiling-point made.
This, when reduced and combined with the mean of the aneroid levels, made the height of the old crater rim, just above the camp, 11,400 ft.
At 6 A.M. the party left the camp, and, hastening to reach the summit of the present crater, were soon ascending rather steep slopes, formed of alternating beds of hard snow and vast quantities of large and perfect felspar crystals, mixed with pumice. And a little farther on they reached the base of the volcano's active cone. Progress now became painfully slow, as the height and cold combined to make it difficult to breathe.
The cone of Erebus is built chiefly of blocks of pumice, from a few inches to a few feet in diameter. Externally these were grey, or often yellow, owing to incrustations of sulphur, but when broken they were of a resinous, brown colour.
At last, just after 10 A.M. on March 10, the edge of the active crater was reached, and the little party stood on the summit of Erebus, the first men to conquer perhaps the most remarkable summit in the world. From measurements made while at the crater's edge, Erebus may be calculated to rise to a height of 13,370 ft. above sea-level.
The report most vividly describes the magnificent and awe-inspiring scene before the eyes of the travellers.
The "Lion" of Erebus. (See page 86)
"We stood on the verge of a vast abyss, and at first could see neither to the bottom nor across it on account of the huge mass of steam filling the crater and soaring aloft in a column 500 to 1000 ft. high. After a continuous hissing sound, lasting for some minutes, there would come from below a big, dull boom, and immediately great globular masses of steam would rush upwards to swell the volume of the snow-white cloud which ever sways over the crater. This phenomenon recurred at intervals during the whole of our stay at the crater. Meanwhile the air around us was extremely redolent of burning sulphur. Presently a pleasant northerly breeze fanned away the steam cloud, and at once the whole crater stood revealed to us in all its vast extent and depth. Mawson's angular measurement made the depth 900 ft., and the greatest width about half a mile. There were at least three well-defined openings at the bottom of the cauldron, and it was from these that the steam explosions proceeded."