The distance of the rock from the mainland complicated the issue very materially. A suitable site had to be prepared on shore as a base, where the stones could be prepared for shipment, while a special steam-tender was necessary to run to and fro. The handling of the workmen had to be carried out upon the lines which were adopted at Skerryvore--namely, the erection of a barrack upon a skeleton framework on the rock, where the men might be left safely for days or weeks at a time. The shore station selected was at Earraid, on the neighbouring island of Mull, because it was the nearest strategical point to the work, and because ample supplies of first-class granite were available in the immediate vicinity, the proprietor, the Duke of Argyll, as in the previous instance, facilitating the work as far as possible. The authority to commence operations was given on March 11, 1867, and this year was devoted to completing preparations, so that in the following season work might be started in earnest and carried on throughout the summer at high pressure. The first task was the erection of the barrack on the rock. The workmen got ashore for the first time on June 25, 1867, and, although landing at all times was trying and perilous, attempts often having to be abandoned owing to the swell, the engineer succeeded in landing twenty-seven times up to September 3, when work had to be suspended until the following year. Despite the shortness of the season, the men made appreciable headway. The iron framework of the barrack was completed to the first tier, while a good beginning was made upon the rock-face in connection with the foundations for the lighthouse. When the autumnal gales approached, everything in connection with the barrack was left secure, the builders being anxious to ascertain how it would weather the winter gales and the force and weight of the waves which bore down upon it. The engineers finally decided upon a tower 107½ feet in height. After trying various curves for the outline, they came to the decision that a parabolic frustum would afford the most serviceable design, as well as providing the maximum of strength. A diameter of 36 feet was chosen for the base, tapering gradually and gracefully to one of 16 feet at the top, with the entrance 32 feet above the base, to which point the cone was to be solid.