MECHANICS AND USEFUL ARTS. 29 



of the capacities of the high and low-pressure cylinders being about as one 

 to two and a half, the steam, may be supposed to be finally expanded in 

 about that ratio, and the effect of each pair is theoretically equal to that 

 of a single cylinder of 76 inches diameter, in which the steam, is cut off at 

 two-fifths of the stroke and expanded through the remainder. There are 

 two vertical air-pumps, one on each side, worked by eccentrics on the 

 upper shafts. There are many details of considerable novelty, among 

 which may be mentioned a set of small valves or cocks suitably connected 

 for working, or rather for " warming " the engines by hand. 



The immense steamship contracted for by the Eastern Steam Navigation 

 Company (England) is in the course of completion, by Mr. Scott Russell. 

 The extreme length on main deck will be 700 feet, being 430 feet longer 

 than the Himalaya steamer; extreme length of keel, 680 feet; extreme 

 breadth of beam, 83 feet; depth of hold, (forming four decks,) 58 feet; 

 length of principal saloon, 80 feet ; height of ditto, 15 feet ; tonnage, 

 10,000, or builders' measurement, 22,000 tons ; stowage for coals, 10,000 

 tons ; stowage for cargo, 5,000 tons ; 500 first-class cabins, with ample 

 space for second and third-class passengers, besides troops, etc., while her 

 screw and paddle engines will be of the aggregate nominal power of 2,800 

 horse. She will also carry an immense quantity of sail. " The principle of 

 construction, as designed by Mr. Brunei, will be similar to that of the tube 

 of the Britannia Bridge. Her bottom, decks, and sides are to be double, 

 and of a cellular form, with two feet six inches between. She will have 

 fourteen water-tight compartments, also two divisional bulk-heads running 

 her whole length. The great length of the ship, it is contended, according 

 to all present experience, will enable her to pass through the water at a 

 greater velocity, with a similar power in proportion to her tonnage, than 

 ordinary vessels now require to make ten knots an hour, and that speed is, 

 in fact, another result of great size. The immense proportions will admit 

 of carrying sufficient fuel to accomplish a voyage round the world. 



The largest ocean steamships (says the Sailors' Magazine] now plying 

 on the Atlantic, bear precisely the proportions in length, breadth, and 

 depth, that are recorded concerning Noah's Ark. The dimensions of the 

 Atlantic steamers are : length, 322 feet ; breadth of beam, 50 feet ; depth, 

 28i feet. The dimensions of the Ark were : length, 300 cubits ; breadth, 

 50 cubits ; depth, 30 cubits. The Ark, therefore, was nearly twice the 

 size, in length and breadth, of these vessels, the cubit being twenty-two 

 inches ; both had upper, lower, and middle stories. After all the equip- 

 ments of forty-two centuries, which have elapsed since the Deluge, the 

 ship -builders have to return to the model afforded by Noah's Ark. 



At the last meeting of the British Association, Mr. Scott Russell gave 

 a lecture upon the progress of naval architecture and steam navigation, 

 including a notice of the large ship of the Eastern Steam Navigation 

 Company. It was mainly in respect to speed that the great improvements 

 in the last twenty years had been made. Within that time the principle 

 and the means of gaining speed had become definitely known, and this 



