The Pamphlet Collection of Sir Robert Stout: Volume 67
Appendix No. 2. — Ascent Of Ruapehu: Extract from Mr. L. Cussen's Report, Dated June, 1886
Appendix No. 2.
Ascent Of Ruapehu: Extract from Mr. L. Cussen's Report, Dated June, 1886.
In my monthly report for April I informed you that on ascending Ruapehu in the early part of that month we found a crateral hollow on its summit containing warm, or probably boiling, water: as this matter may be of interest at the present time, it may be well to give a few details and a short description of the mountain, so far as I can from the few notes which I was able to make in the limited time I could devote to the subject, my object, of course, being to complete the trigonometrical observations at the trig, stations in time to descend to our camp before night. We ascended the mountain from the western side, following a long and tolerably regular ridge which runs down from the top of the cone to its base. The ascent was not very difficult: we accomplished it in four and a half hours from our camping-ground, which was situated 5,000ft. above the sea-level; we had therefore 4,000ft. to ascend, nearly 3,000ft. of which was over frozen snow. As we ascended, on all sides of us were examples most various and instructive of volcanic phenomena, and the forms and shapes assumed by lava in cooling. The most remarkable feature of the mountain is the crater-lake on its summit. This lake is situated at the bottom of a funnel-shaped crater, its steep sides being mantled with snow and ice. I had no time for measurements to ascertain the correct dimensions of the lake, and its peculiar surroundings made it difficult to estimate them with any degree of accuracy. The water seemed to me to occupy a circular basin about 500ft. in diameter; it is situated inside the two peaks, Paritetaitonga and Ruapehu, which are about 60 chains apart on the southern portions of the mountain; the lake would be about 300ft. below the peaks, and quite inaccessible, except with the aid of a long rope, and even then the descent over the icy masses would be attended with danger and difficulty. On first reaching the top of the peak I noticed small clouds of steam floating over the surface of the lake; on watching it more closely the water appeared now and then to assume a rotary movement; eddies and whirlpools seem to pass through it from the centre to the sides, steam or vapour flashing up from the eddies.
When observing angles at Paritetaitonga, although the stones which formed the station-mound were frozen hard together, my instrument would not remain level; the same thing occurred at Hauhungatahi station, eight miles to the westward of Ruapehu, which was likewise frozen hard when I was observing there. Three years ago, when taking angles on Ngauruhoe, I found the same difficulty in keeping my instrument level, although the ground on which it stood was formed of a solid conglomerate mass.*
* Mr. A. D. Wilson, writing on the 20th July, reports the same trouble. He says: "I experienced great difficulty in keeping my instrument level when observing at Hauhungatahi, even though the ground was ironbound with frost. I ascribe this less to present volcanic action than to the place where the trig, is being an old crater, which having been filled up with very loose materials never properly consolidated, the slightest weight upon the surface is sufficient to depress it. I am led to assume this from the character of the stuff taken out when digging the hole of the tube, which looked as if it had first been burnt and then put through a crushing-machine."