The engineers hurriedly evolved a tower which would meet the Government needs. It was thought that the extreme height of the rock would lend itself to the erection of a building which, while possible of early completion, would be adequate for subsequent purposes. The materials for the light, together with a lantern, and a second building for the storage of the oil and other requisites, were shipped northward from Glasgow. Simultaneously the engineers, with another small gang of men who had already reached the rock, pushed on with the preliminary preparations, so that when the constructional vessel arrived erection might go ahead straightforwardly and rapidly. [Illustration: _By permission of the Lighthouse Literature Mission._ THE DHU-HEARTACH LIGHTHOUSE. To the left is the lower part of the temporary structure in which the builders lived while erection was in progress.] The engineers tried the rock from all sides to find a safe landing. This was no light matter, owing to the steepness of the slope even upon the easiest face of the pinnacle. The attempt represented a mild form of mountaineering, for the sea had battered away the projection of the lower-lying levels, and the men found it trying to effect a foothold, even in stepping from the boat on to the rock. They had to climb hand over hand up the precipice, with life-lines round their waists, taking advantage of every narrow ledge. With infinite labour they gained the summit, and then they found that there was just sufficient space, and no more, upon which to plant the lighthouse buildings. The top was cleared quickly, and then the advance party set to work to improve the landing-place on the south side of the rock for the reception of the building materials. A small site was prepared with great difficulty, as the tough rock offered a stern resistance to the chisels, drills, and wedges; while in addition the men had to cut steps in the flank of the rock to facilitate the ascent to the site. On September 14, 1854, the constructional vessel _Pharos_ hove in sight, and, the weather being favourable, the landing of the material was hurried forward. The men had to become pack-animals for the time, carrying the loads on their backs. In this manner they tramped laboriously up and down the cliff-face with material and stores of all descriptions. The heavier and bulkier parts were hauled up by rope and tackle, a few feet at a time, and this task was quite as exacting. In all, 120 tons were conveyed to the top of the crag. Construction was hastened just as feverishly, and on October 11, 1854, twenty-six days after the _Pharos_ anchored off Muckle Flugga, the North Unst light shone out for the first time. This is probably one of the most brilliant exploits that has ever been consummated in connection with lighthouse engineering, the merit of which is additionally impressive from the fact that almost everything had to be accomplished by manual effort.