MECHANICS AND USEFUL ARTS. 53 



thing neAv in their principles. The power of the engine, in propor- 

 tion to the size, and draft of water, will be very great, about live 

 times that of the steamers of the Cunard line. In an ordinary vessel 

 such power cannot be applied, as it would tear the hull to pieces. In 

 the present case, however, it is made practicable by the peculiar in- 

 ternal structure as well as by the novelty of the mode. As will be 

 seen by the figures given above, the floor of the vessel is unusually 

 flat, and its draft of water exceedingly small. At the same time the 

 bow is unusually sharp. In fact, the model is the result at once of a 

 great deal of practical experience, as well as of laborious and careful 

 mathematical calculations, and it is believed that its lines and form 

 are such as to produce the least possible resistance in passing through 

 the water. Here, then, we have the grounds for the estimate that an 

 average speed of 20 miles an hour will be attained in storm as well as calm : 



1. Sharpness of bow, perfection of curves, and light draft and 

 buoyancy. 



2. Enormous power of engine. 



The daily consumption of coal will be about 90 tons, and the stock 

 for a passage about 300 ; no freight is to be taken. The vessel >\iil 

 carry no masts, but will be arranged with jury-masts to rig in cases of 

 necessity. 



The Clipper Slip Great Republic. During the past summer a 

 gigantic clipper, bearing the above title, has been constructed and 

 launched by Donald McKay, Esq., of East Boston, Mass. This vessel 

 is the largest merchantman ever constructed, has a capacity of about 

 4,000 tons. She is 325 feet long, 53 feet wide, and her whole depth 

 is 37 feet. The keel, for 60 feet forward is gradually raised from a 

 straight line, and curves upwards into an arch, where it blends with 

 the stem so that the gripe of her forefoot, instead of being angular 

 like that of other vessels, is the complete arch of a circle. This arch, 

 both inside and outside is formed of solid oak, and binds all the joints 

 together, so that the greater the pressure the more firmly will the arch 

 be knit together. Strength, however, is only one reason for adopting the 

 arched form for her forefoot: the other reason is, to facilitate her 

 working, and at the same time to make her entrance as clean as 

 possible, to obviate resistance. She has vast surface of floor, with 

 about 20 inches dead rise, and a very long and clean run, which, 

 however, as it rises, is spread out to prevent her settling aft. Her 

 lines are concave forward and aft up to a few feet above the load 

 displacement line, but become gradually convex as they ascend and 

 form her outline on the planksheer. The angular form of her bow, 

 however, is preserved entire. Her sides are arched, or swell some- 

 what like those of a ship of war, but not so much in proportion to her 

 size ; and her sheer is graduated her whole length, with just sufficient 

 rise forward, to impart ease and grace to the bow. She has a waist 

 of nine narrow strakes defined between the mouldings of the upper 

 wale and the^planksheer, and every line and moulding is graduated to 

 correspond with her sheer. Her stern is semi-elliptical in form, and 

 corresponds well with her after body. She has four complete decks. 



