The superior lightness, durability, and elasticity of steel over iron renders it more suitable for many of the uses te which we put that metal, and one of the last substitutions that has been made is the construction of ships of steel. It is a well-known fact that within certain limits crank ships sail better than steady ones, because of their superior elasticity, and they give to the impact of the waves, and glide through the opposing forces, when a steadier and safer ship would inflexibly receive the whole force, and not move an inch. This fact having been considered, the homogeneous metal, which is a sort of halfway house between steel and iron, is being largely employed in ship-building, and there are now in England many in the course of construction. The first vessel ever built of steel was the small steam launch for the Livingston Expedition up the Zambesi river, and another one, the Rainbow of 160 tuns has just been launched from Mr. Laird's works on the Mersey, which is intended for the navigation of the Niger.