Friday, 13th.
To-day the building-artificers laid the Seventy-fifth and Seventy-sixth courses, consisting each of 12 stones, and the seamen landed 11 stones, being the remainder of the Patriot’s cargo.
Saturday, 14th.
The Seventy-seventh and Seventy-eighth courses were laid to-day: the landing-master’s crew discharged 26 blocks of stone, and 20 dove-tailed joggles from the Smeaton, and landed them on the Rock. As it blew very fresh from the S.W., it was a hard day’s work for the seamen, who commenced this morning as early as 2 o’clock to load the praam-boats, and it was between 7 and 8 in the evening before the boats returned on board of the Tender for the night.
Sunday, 15th.
The artificers laid the Seventy-ninth and Eightieth courses to-day, consisting of 12 stones each, and had no less than seven and a half hours of extra time, having been at work from 4 o’clock this morning till 9 in the evening, owing to some difficulty which occurred in laying the course, in which the upper storm-hinge cases occurred.
Monday, 16th.
Ring-bar course laid.
Floors described.
The artificers laid the Eighty-first course, consisting of 12 stones from Craigleith Quarry, being one of these worked at Edinburgh, in which a groove, for an iron-ring, was cut, as an additional security for the superincumbent weight of the cornice. In the First course of the Dome of St Paul’s of London, a continuous chain had been sunk into a groove, in order to bind the haunches of the arch more firmly together. Mr Smeaton, alluding to this in his Narrative, also inserted a chain into each of his floor-courses at the Edystone Light-house. Being of an arched form, these chains inserted into grooves, cut in the haunch-courses of arches, have a tendency to counteract their pressure outwards. At the Bell Rock, the writer, however, designed the floors in such a manner that each projected from the outward wall of the building towards the centre, and the whole being grooved in a lateral direction, in the joints, like the deals of a common floor, became as one stone, having a perpendicular pressure upon the walls. Even in the dome-roof of the library, though it has a spherical appearance within, yet the stones are all laid upon horizontal beds, the dome being formed by hollowing the under beds, and making them overlap or project inward beyond each other, the pressure being still perpendicular upon the walls, instead of thrusting outwards, as in the case of an arch.