This has now (1895) been far surpassed.—_Vide infra._
The actual speed attained by steam-ships with engines of a given power and a given section amidships will depend greatly upon the shape of the vessel. When the bow is sharp, the water displaced is more gradually and slowly moved aside, and therefore does not offer nearly so much resistance as in the opposite case; but the greater part of the power required to urge the vessel forward is employed in overcoming a resistance which in some degree resembles friction between the bottom of the vessel and the water.
The wonderful progress which has, in a comparatively short time, taken place in the power and size of steam-vessels, cannot be better brought home to the reader than by a glance at Fig. 64, which gives the profiles of four steamships, drawn on one and the same scale, thus showing the relative lengths and depths of those vessels, each of which was the largest ship afloat at the date which is marked below it, and the whole period includes only the brief space of twenty years!—for this, surely, is a brief space in the history of such an art as navigation. All these ships have been named in the course of this article, but in the following table a few particulars concerning each are brought together for the sake of comparing the figures:
┌─────┬─────────────────┬─────────────────┬────────┬────────┐ │Date.│ Name. │ Propulsion. │Length. │Breadth.│ ├─────┼─────────────────┼─────────────────┼────────┼────────┤ │1838 │_Great Western_ │Paddles │236 ft. │ 36 ft. │ │1844 │_Great Britain_ │Screw │322 ft. │ 51 ft. │ │1856 │_Persia_ │Paddles │390 ft. │ 45 ft. │ │1858 │_Great Eastern_ │Screw and paddles│690 ft. │ 83 ft. │ └─────┴─────────────────┴─────────────────┴────────┴────────┘
Several passenger ocean-going steamships have been built since the _Persia_, of still greater dimensions, and of higher engine power. These have generally been surpassed in late years by some splendid Atlantic liners, such as the sister vessels owned by the International Navigation Co., and now named respectively the _New York_ and the _Paris_. The _City of Rome_, launched in 1881 by the Barrow Steamship Co., is little inferior in length to the _Great Eastern_, although the tonnage is only about one-third. The _City of Rome_ is 560 ft. long, 52 ft. wide, and 37 ft. deep. Her engines are capable of working up to 10,000 indicated horse-power. Fig. 65 is a sketch of this ship, and shows that she carries four masts and three funnels. The main shaft measures more than 2 ft. across, and the screw-propeller is 24 ft. in diameter. She has accommodation for 1,500 passengers, and is fitted with all the conveniences and luxuries of a well-appointed hotel. The International Navigation Co.’s ship _Paris_, has made the passage across the Atlantic in less than six days, and appears to be the fastest vessel in the transatlantic service. In August, 1889, she made the run from shore to shore in 5 days, 22 hours, 38 minutes.