Various conjectures were made as to the cause of the destruction of the barrack. Those who saw it erected were so confident of its stability, that they could not avoid connecting its failure with some injury received from the wreck-timber, which had come ashore on the island of Tyree, two days after the supposed date of the accident. In this opinion they were strengthened by the total destruction of the cranes and other objects on the rock, forgetting that the timber of the barrack itself, when once let loose, must of necessity have proved even a more powerful agent of destruction than the driftwood of the wreck. But whatever doubt may exist as to the first cause of the injury, there seems good reason to suppose that the dismemberment of the parts of the structure had commenced with the removal of the horizontal braces, and that the beams, having thus more liberty for play and tremor, had gradually shaken loose the fixtures at the top, which consisted of straps _c_ _c_, passing right over the tops _a_ _a_, of the beams and _b b_, the hexagonal quoin of hardwood already noticed at p. 88, which were secured by means of a central bolt _d_, and finally girt outside by a ring, _e_ _e_, as shewn in the annexed woodcut (No. 10.) The moment this dismemberment occurred, the beams would be free to work their own destruction; and the enormous leverage which they exerted, when dashed to and fro by the breakers, would soon snap the iron stancheons at the base, and throw all loose to the waves. The only remaining beam was that which was supported against a ledge of rock, and which had received the sea from the opposite direction to that in which it was found lying. That beam, however, although firmly lashed to the rock by the men who first visited it after the accident, along with Mr Charles Barclay, also disappeared in the course of the winter. As a proof how severely these beams had been dashed by the waves, I may state, that the only remaining part of a beam which I saw attached to the iron stancheons, when I landed in the following spring, was so thoroughly riven and _shaken_ as to be quite like a bundle of lathwood. ~Preparations for a new barrack.~ [Illustration: No. 11.]