MECHANICS AND USEFUL ARTS. 33 



to the officers, whose apartments are at present only marked by a. few up- 

 rk-hts, rising ten or twelve feet above the main deck. Below the berths of 



O 7 ~ 



the seamen arc two enormous cavities, for cargo, of which five thousand tons 

 can be carried, besides coals enough for the voyage to Australia, making 

 about as many tons more. 



The weight of this huge ship being 12,000 tons, and coal and cargo about 

 18,000 tons more, the motive power to propel her twenty miles per hour 

 must be proportionate. If the visitor walks aft, and looks down a deep 

 chasm near the stern, he will perceive an enormous metal shaft, 160 feet in 

 length, and weighing sixty tons ; this extends from the engine-room nearest 

 the stern to the extremity of the ship, and is destined to move the screw, the 

 four fans of which are of proportionate weight and dimensions. If next he 

 walk forward, and look over the side, he will see a paddle-wheel considerably 

 larger than the circle at Astley's; and when he learns that this wheel and its 

 fellow will be driven by four engines, having a nominal power of 1,000 

 horses, and the screw by a nominal power of 1,600 horses, he will have no 

 difficulty in conceiving a voyage to America in seven and to Australia in 

 thirty-five days. The screw engines designed and manufactured by Messrs. 

 James Watt & Co., are far the largest ever constructed, and when making 

 fifty revolutions per minute, will exert an effective force of not less than 

 8,000 horses. It is difficult to realize the work which this gigantic force 

 would perform if applied to the ordinary operations of commerce ; it would 

 raise 132,000 gallons of water to the top of the Monument in one minute, or 

 drive the machinery of forty of the largest cotton-mills in Manchester, giving 

 employment to from thirty to forty thousand operatives. There arc four 

 cylinders, each about twenty-five tons, and eighty-four inches in diameter. 

 The crank-shaft, to which the connecting rods are applied, weighs about 

 thirty tons. The boilers are six in number, having seventy-two furnacesj 

 and an absorbent heating-surface nearly equal in extent to an acre of ground. 

 The total weight exceeds 1,200 tons, yet so contrived that they can be set in 

 motion or stopped by a single hand. 



Sails will not be much needed, for in careering over the Atlantic at twenty 

 miles per hour, with a moderate wind, they would rather impede than aid ; but 

 in the event of a strong wind arising, going twenty-five miles per hour in the 

 course of the vessel, sails may be used with advantage, and the Great Eastern 

 is provided accordingly, with seven masts, two square-rigged, the others cany- 

 ing fore and aft sails only. The larger masts will be iron tubes, the smaller of 

 wood. The funnels, of which there will be five, alternating with the masts, are 

 constructed with double casings, and the space between the outer and inner 

 casings will be filled with water, which will answer the double purpose of pre- 

 venting the radiation of heat to the decks, and economizing coal by causing the 

 water to enter the boilers in a warm state. Her rigging will probably cause 

 most disturbance of ideas to nautical observers, for, besides the unusual 

 number of masts, she will want two most striking features of all other vessels, 

 namely, bowsprit and figure-head. Another peculiarity is the absence of a 

 poop. The captain's apartment is placed amidships, immediately below the 

 bridge, whence the electric telegraph will flash the commander's orders to the 



