Page:The fairy tales of science.djvu/367

 and by these patterns the plates were cut into their required shape by the huge steam-shears, in exactly the same manner as a tailor cuts out various portions of a garment. The "list," or inclination given to each plate, was the next process; and this was produced by passing the plate through a system of rollers, which could be so reversed in their action, and so adjusted, as to give any required curve.

The Leviathan was not built in the usual manner; there was no skeleton to indicate what it was about to become. The reason of this was, that on account of the enormous length of the ship, it was necessary to make use of a different mode of construction to that generally pursued in building ships, and for this purpose the tubular principle, so successfully carried out by Robert Stephenson in the Menai Bridge, was adopted.

The framework of the ship may be described as consisting, primarily, of thirty-five horizontal webs or ribs of iron plate, each nearly three feet wide, and immensely strengthened at all the points of junction. They extend from end to end of the vessel side by side at the bottom, and one over the other at the sides, at distances varying from three to five feet apart. On either side the uppermost web is about five feet above low-water mark. These webs are crossed by huge partitions of a similar construction placed just sixty feet apart. Plates of the best and toughest iron are riveted on each side of the thirty-five longitudinal webs or ribs, so as to