After a careful inspection, the party retired to their sloop, which lay off until the tide had fallen, when Smeaton again landed, and the night being very calm, he continued on the rock until nine in the evening. On the 23rd he again landed, and pursued his operations; but this time he was interrupted by the ground-swell, which dashed the waves upon the reef, and, the wind rising, the sloop was forced to put back to Plymouth. During this visit, however, our engineer had secured some fifteen hours' occupation on the rock, and taken the dimensions of all its parts, to enable him to construct an accurate model of the foundation of the proposed structure. To correct the drawing, however, and to insure the utmost exactness, he determined upon attempting an eighth and final voyage of inspection on the 28th of April. [Sidenote: The eighth attempt.] Again the violence of the sea foiled him in his design. Another fortnight passed, a fortnight of unfavourable weather; but the time was not wasted. The engineer elaborated his design, and made all the preliminary arrangements to proceed with the work. He also drew up a careful code of regulations for the instruction and government of the artificers and others who were to be employed upon it. And this being done, he arranged for a journey to London, but not until he had paid three more visits to the rock for the purpose of correcting his measurements. In August 1756, as we have already related, the erection of the lighthouse was begun, and operations were continued until the end of November, in spite of the obstacles offered by a violent sea and unfavourable winds. The return of the workmen to port, in their store-vessel the _Neptune_, was safely accomplished, though the voyage was not unattended with danger. [Sidenote: A storm at sea.]