A careful study of the construction of this remarkable vessel establishes the fact that over fifty years ago Brunel and Scott Russell produced in the _Great Eastern_ a ship which stands as a model for all time. Realising, in the first place, how vulnerable is an iron vessel which carries only a single skin, they decided to provide a double skin and construct the ship with two separate hulls, placed one within the other and firmly tied together by a system of continuous longitudinal and lateral web-plates or frames. By reference to the cross-section, published on page 83, it will be seen that the double-skin construction extended entirely around the hull, and was carried up to a continuous plate-iron lower deck, which was from 8 to 10 feet above the water-line, the distance varying with the draft of the ship. The two skins were placed 2 feet 10 inches apart and they were tied together by 34 longitudinal web-members, which ran the entire length of the double hull, and divided the space between the two skins into separate watertight compartments. These were themselves further subdivided by a series of transverse webs which intersected the longitudinal webs. The cellular construction thus provided extended from the aftermost bulkhead right through to the bow, to which it was carried for the purpose of protecting the forward part of the ship against the effect of collision with icebergs, which at that early day were recognised as constituting a serious menace to navigation. The inner skin was not continued aft of the aftermost bulkhead, for the reason that at the stern it would have been unnecessary and somewhat inconvenient. [Illustration: TITANIC BUILT 1912 MAURETANIA BUILT 1906 GREAT EASTERN BUILT 1858 TWO EXTREMES IN PROTECTION, AND A COMPROMISE] The double hull was closed in by a watertight iron deck (the lower deck), which served to entirely separate the boiler- and engine-rooms and the holds from the passenger quarters. Above the lower deck the hull was built with a single skin, which terminated at a flush, continuous, cellular steel deck, corresponding to the shelter deck of modern steamships, which extended unbroken from stem to stern. This deck was an unusually rigid structure. Its upper and lower surfaces were each one inch in thickness, and each consisted of two layers of half-inch plating riveted together. The double deck thus formed was two feet in depth, and the intervening space was intersected by longitudinal girders, the whole construction forming an unusually stiff and strong watertight deck, which was admirably suited to meet the heavy tensional and compressive stresses, to which a ship of the length of the _Great Eastern_ is subjected when driving through head seas.