 The new barrack withstood the violence of the storms during the winter of 1839 – 40 . Work re @-@ commenced on the rock on 30 April 1840 , and after the arrival of the new steamer Skerryvore the carefully fashioned blocks began to arrive on site . The first one was laid by John Campbell , 7th Duke of Argyll on 4 July . His son George later wrote : 
