It was necessary that every thing intended to be left on the Bell Rock during the working season, should have as little buoyancy as possible, and as it would have been extremely inconvenient to have removed the waggons from the rock, which were to be employed in conveying the blocks of stone from the landing-places to the Light-house, they were constructed entirely of iron, excepting two pieces of oak timber, which were bolted upon the top, to form a seat for the stones. These waggons, represented in Plate X., moved upon four trucks or wheels of cast-iron, measuring one foot two inches in diameter, placed two feet six inches asunder, being the length of the axle, and breadth of the railway. Each waggon was provided with a handle, which shifted at pleasure to either end, for the conveniency of reversing the motion, without the necessity of turning the vehicle. But what was more peculiar to these waggons, was a joint in the middle of the perch or double frame, connecting the wheels, by means of which they were made applicable to the circular tracks of the railway round the site of the building. [Sidenote: Triangular Crane.] Connected with the cast-iron railways, preparations were also made at the eastern landing place, for lifting the stones by means of cranes or other machinery from the Praam-boats, and laying them upon the waggons to be conveyed to the building. After a good deal of consideration, patterns were prepared for an apparatus consisting chiefly of six pieces of cast-iron, four of which measured 12 feet in length, and of a corresponding strength. As will be seen in Plate XI., these bars met at the top in the form of two sets of sheers, but their lower ends were placed about 9 feet asunder. Connected with these, a pair of sheers were set up, which were moveable upon a bolt, and worked with a crab or winch machine, the whole being strongly batted to the rock. When the moveable pair of sheers, with their attached chain and hook, were suspended outwards over the stone to be lifted from the praam, the chain was hooked to the Lewis-bat, previously inserted into the block. The sheers were then raised till they were brought to a perpendicular position, when the motion of the winch was reversed, and the sheers were lowered inwards upon the wharf, and the stone thus laid upon the waggon. The chain was then unhooked, and the sheers were ready for lifting another stone, as will be better understood by referring to Plate XI., with its letter-press description. [Sidenote: Crane with moveable Beam.]