From the wasting effects of the sea, the Bell Rock is formed into numerous benches and gullies, and its surface is consequently extremely rough and irregular. The site of the Light-house being in a central position on the rock, it became necessary to make some provision for conveying the large blocks of stone speedily from the respective landing-places to the site of the building; or at least within the range of the cranes or machinery to be employed in laying them. In ordinary situations, the most obvious method would have been to clear away the inequalities of the rock; but here, from the lowness of its position in the water, such an operation would have been extremely tedious and difficult. Besides, every portion of the Bell Rock was held sacred, excepting in so far as it was absolutely necessary to excavate or remove part of it, in fixing the Beacon-house, and in preparing the foundation of the Light-house. Instead, therefore, of quarrying the rock, the writer found that the most advisable process would be, to lay cast-iron railways round the site of the Light-house, projecting to the several landing-places, on which waggons could easily be wheeled in all directions, as will be seen by tracing the dotted lines on Plate VI. For this purpose, patterns were prepared in the course of the winter, from which castings of the several compartments of the railways were made by Mr John Baird, of the Shotts Iron Works. These rails were cast in lengths of four feet, and supported upon props and frames of cast-iron, varying in height from six inches to five feet, according to the inequalities of the rock, that the whole might be laid upon one level. Besides the tracks for the wheels of the waggons, it was necessary also to provide a tracking-path of the same metal, which was formed of ribbed work, rested upon the supports of the rails, as will be understood from the diagrams in Plate X. The waggon-tracks were of the form technically termed Plate-rails, which were found convenient for making the necessary fixtures. The edge-rail is less liable to friction, and is certainly greatly preferable to the plate-rail, where the track is liable to be impeded with dust, and other adventitious matters; objections which do not apply at the Bell Rock, where the rails were every tide considerably under water. [Sidenote: Waggons.]