Stones laid at the depth of about 14 feet under high-water mark, required more than merely laying them on their respective beds, and trusting to their own gravity. For this purpose nothing seemed to be so well adapted as the oaken trenails which Mr Smeaton used in the erection of the Edystone Light-house. Two jumper-holes, of an inch and a half in diameter, had accordingly been drilled through each stone, which were continued or perforated to the depth of six inches into the rock or course immediately below, which became the most tedious part of the building operation. When the oaken trenail was inserted into the hole, it had a saw-draught across the lower end, into which a small wedge was inserted: and when driven home, it became quite firm. The trenail was then cut flush with the upper bed of the stone, and split with a chisel, when another wooden wedge was inserted and driven into the upper end of the trenail, as represented in diagram 10. of Plate X. Nor was this all, for, in following up Mr Smeaton’s principle, two pairs of oaken wedges, as represented in Plate X., Fig. 11. were also driven gently into the perpendicular joints, prior to grouting them with mortar. The whole stones of a course had thus to be laid with great nicety, corresponding to a number of checks and marks, previously arranged in the work-yard, that the wedges might fit without trouble at the Rock, and preserve the respective positions of the superincumbent courses, and make band throughout the whole fabric. [Sidenote: Friday, 5th.] [Sidenote: 16 Stones laid.] The boats landed the artificers this morning at half-past 5 o’clock, and the foundation-pit being cleared of water, seven stones were laid and secured with trenails by 8 o’clock. The artificers are again landed at 6 P. M. and in the course of two hours nine additional stones were laid. [Sidenote: Saturday, 6th, till Wednesday, 10th.] [Sidenote: 92 Stones laid.] From Saturday the 6th till Wednesday the 10th inclusive, the weather and tides were favourable, which afforded an opportunity of landing both with the morning and evening tides, and in the course of these five days twenty-six hours’ work were obtained, and ninety-two stones were laid. The landing-master’s crew also continued their operations in delivering the Smeaton, and laying her cargoes on the Rock. [Sidenote: Thursday, 11th.] [Sidenote: 11 Stones laid.] The boats landed the artificers to-day at 9 A. M., and in about three quarters of an hour the site of the building was cleared of water, when eleven stones were laid in the course of an hour and three quarters. There being a considerable swell in the sea to-day from south-east, the praams could not land any materials upon the Rock at high-water, and nothing could be done in this way at low-water, as the Railways were not yet in a working condition. [Sidenote: A party of Gentlemen narrowly escape being drowned.]