 Work for the season lasted only until 11 September , by which time the barrack legs had been secured although not the main structure . Less than two months later Stevenson received a letter from the storekeeper at Hynish , Mr. Hogben . It began : " Dear Sir , I am extremely sorry to inform you that the barrack erected on Skerryvore Rock has totally disappeared . " The structure had been destroyed during in a gale on 3 November and four months effort had been wasted . Stevenson hired a boat to take him out to inspect the damage the same day he received this news . Firm in his self @-@ belief , he resolved to build a stronger but otherwise identical replacement . Work began in April 1839 and by early September the completed barrack stood 60 feet ( 18 m ) above the rock . Entry was via ladders attached to the legs that led into the lowest level containing a kitchen . The middle level contained two cabins , one for Stevenson , the other for his master of works , whilst the top level provided sleeping quarters for a further 30 to 40 men . 
