Having fixed the instrument on the rocks quite clear of the ice, the Professor determined the direction of a supposed line perpendicular to the axis of the glacier. He then sought for a conspicuous and well-defined object on the opposite side of the valley, as near as possible to that direction. In this he was greatly helped by Captain Wopper, who, having been long accustomed to look-out with precision at sea, found it not very difficult to apply his powers on land.

“There’s a good land-mark, Professor,” he said, pointing towards a sharply-cut rock, “as like the Dook of Wellington’s nose as two peas.”

“I see it,” said the Professor, whose solid and masculine countenance was just the smallest possible degree flushed by the strong under-current of enthusiasm with which he prosecuted his experiments.

“You couldn’t have a better object than the pint o’ that,” observed the Captain, whose enthusiasm was quite as great as, and his excitement much greater than, that of the Professor.

Having carefully directed the telescope to the extreme point of the “Dook’s” nose, the Professor now ordered one of his assistants to go on the glacier with a stake. Lawrence descended with him, and thus planted his foot on glacier-ice for the first time, as Lewis afterwards remarked, in the pursuit scientific knowledge.

While they were clambering slowly down among the loose boulders and débris which had been left by the glacier in previous years, the Professor carefully sketched the Duke of Wellington’s nose with the rocks, etcetera, immediately around it, in his notebook, so that it might be easily recognised again on returning to the spot on a future day.

The assistant who had been sent out with the first stake proved to be rather stupid, so that it was fortunate he had been accompanied by Lawrence, and by the guide, Antoine Grennon, who stirred up his perceptions. By rough signalling he was made to stand near the place where the first stake was to be driven in. The telescope was then lowered, and the man was made, by signals, to move about and plant his stake here and there in an upright position until the point of intersection of the spider’s threads fell exactly on the bottom of the stake. A pre-arranged signal was then made, and at that point an auger hole was bored deep into the ice and the stake driven home.

“So much for number one,” said Captain Wopper, with a look of satisfaction.

“They won’t fix the other ones so easily,” observed the Professor, re-examining the stake through the telescope with great care.

He was right in this. The first stake had been planted not far from the shore, but now Lawrence and his party had to proceed in a straight line over the glacier, which, at this steep portion of its descent into the Vale of Chamouni, was rent, dislocated, and tortured, to such an extent that it was covered with huge blocks and pinnacles of ice, and seamed with yawning crevasses. To clamber over some of the ice-ridges was almost impossible, and, in order to avoid pinnacles and crevasses, which were quite impassable, frequent détours had to be made. If the object of the ice-party had merely been to cross the glacier, the difficulties would not have been great; but the necessity of always returning to the straight line pointed out by the inexorable theodolite, led them into positions of considerable difficulty. To the inexperienced Lawrence they also appeared to be positions of great danger, much to the amusement of Antoine, who, accustomed as he was to the fearful ice-slopes and abysses of the higher regions, looked upon this work as mere child’s play.