56 ANNUAL OF SCIENTIFIC DISCOVERY. 



collected in the openings, the plan was rendered more healthy. More- 

 over, in the new method, there is freedom from rats and other vermin, 

 and above all, the plan is particularly adapted to men-of-war, from 

 there being no iron strapping or iron knees, and the sides being solid, 

 there would be consequently less splinterings from shots, and particu- 

 larly healthy in warm climates." 



Messrs. Scott, Russell & Co. of England, have the contract to 

 build for the Eastern Steam Navigation Company the largest ship 

 ever heard of in the world, which is to carry sufficient fuel for 

 the entire voyage to and from India or Australia. Her length is 

 to be 680 feet ; breadth, 83 feet ; depth, 58 feet ; with screw and paddle 

 engines of aggregate nominal horse-power of 2600. In addition to 

 taking from 4000 to 6000 tons of coals, she will be able to carry 

 5000 tons measurement of merchandise, and will have 500 cabins for 

 passengers of the highest class, with ample space for poops. and lower 

 class passengers. The whole of her bottom, and up to 6 feet above the 

 water line will be double and of a cellular construction, so that any 

 external injury will not affect the tightness or safety of the ship. The 

 upper deck will also be strengthened on the same principle, so that 

 the ship will be a complete beam, similar to the tube of the Brittania 

 bridge. It will be divided into ten water-tight compartments. She 

 will have separate sets of engines, each with several cylinders ; and 

 separate boilers will be applied to work the screw, distinct from those 

 working the paddle wheels, so that in the event of temporary or even 

 permanent derangement of any one of the engines, or of either the 

 paddle wheels or the screw, the other engines and propellers would 

 still be available. It is computed that her great length will enable her 

 to pass through the water at the velocity of fifteen knots an hour, and 

 by the great speed, combined with the absence of stoppages for coal- 

 ing, the voyage between England and India, via the Cape, may be 

 accomplished in thirty or thirty-three days, and between England and 

 Australia in thirty-three or thirty-six days. It is said that the ship 

 will become, by its construction, a beam of sufficient strength to meet 

 any strain to which it can be subjected, and will consist of so many 

 distinct compartments that no local injury, however serious, will affect 

 its buoyancy to any dangerous extent. Journ. Soc. Arts. 



Improvements in Propellors. In a patented improvement by J. 

 Burch, of England, the propulsion is not effected by a disc, but by 

 vanes or helical sections, which he calls " fins," set in the circumfer- 

 ence of a disc, or wheel, to which the corresponding lines of the ves- 

 sels are prolonged, so as to form a kind of cylindrical-shaped projec- 

 tion, from the position of the disc tapering aft to the stern post, and 

 forwards forming a continuation of this gwasz'-cylinder, or trunk, to a 

 little abaft the beam. Above and below the disc are apertures for the 

 passage of the fins. Six vanes are set upon the disc, and, revolved 

 by the motive power, propel the vessel. The advantages alleged are, 

 that the truncated lines act in the manner of Griffith's globular center, 

 in nullifying the central resistance, which chokes the ordinary screw, 

 an object which is a grand desideratum, if attainable. " The advan- 

 tages," says the inventor, " gained by this arrangement, consists in 



