After a good deal of trouble, owing to the lowness of the Rock and the smallness of its surface, the six main beams, each nearly 50 feet long, were raised on end by means of shear-poles, and the iron straps which passed over the top of them, and the ring which embraced the whole so as to secure them at the top, were fixed with much care. The temporary guys were removed on the afternoon of the 18th August. A plummet suspended from the centre of the quoin, after all the six beams were in their places and the stancheons had been run up with lead, came within half-an-inch of the centre bar, which was about 40 feet below the point of suspension, thus indicating an angular deviation of less than 4′. This is a very good approximation, under all the circumstances with which we had to contend; and it is chiefly to be imputed to the very accurate measures pursued in the workyard of the contractor at Greenock, by Mr George Middlemiss, foreman of the carpenters (who then acted as superintendent of the contract works), and whose intelligence and zeal made him, at all times, able and ready to do full justice to all my suggestions for incurring as little loss of time on the Rock as possible. The operation of fixing these six beams, which formed, by their union, a hexagonal pyramid of about 44 feet high, and about 34 feet in diameter at the base, occupied only six days, including the cutting of the seats and the boring of the holes in the Rock. Much labour and time were consumed in the mere moving of beams, each weighing about 13 cwt., over the rugged surface of the Rock, for which purpose we could only use a small set of shear-poles, with crabs and blocks, and tackle purchase; and it sometimes happened, that merely for the purpose of moving a beam, it was necessary to place a special ring-bolt for holding a _snatch-block_ for a few minutes, in spite of all the care and forethought which had been bestowed, in selecting the most advantageous positions for placing them, before the work of raising the beam was begun. Nor was the necessity for securing every loose material by means of lashings to the Rock, before leaving for the night, an insignificant source of delay; for we were sometimes forced by the waves or the darkness, which drove us from our work, to lower a beam which was just ready for being fixed and to replace it in a safe situation. ~Pyramid completed.~ On Saturday the 18th August, the pyramid having been successfully erected, the men were busied for two hours, before embarking for the vessel, in collecting and lashing all the loose materials to the Rock, for the sky gave some indications of a change. As we took to the boats, I looked at the result of our labours with some satisfaction, not unmingled with gratitude. ~Mode of living while erecting the Barrack.~