The performance of the Nautilus was satisfactory enough to lead the tylmiraby to expedite the fieirhing of the Mao-witch, an iron-clad gun-vessel of 778 tons and 160 horse-power. That wheel is rotated by an engine having three separate cylinders each 38+ in. diameter by 3 ft. 6 in. stroke. The vessel was built at the Thames iron-works, and engined by Measrs. J. & W. Dudgeon of Illackwall. Its turbine-wheel is 14 ft. dia meter; it rotates (at full engine-power) 30 times per minute. The brass discharge nozzles, which measure 24 in. by 19+. are continued along the outside of the vessel 8 ft. on each side of the center; the lower lips of the discharge-nozzlt s arc 8 in. below water line, the remainder of the aperture being above water. The Watery/Mit is flat-bottomed and doulde-ended, i.e.. she has a rudder at each end, so that she can steer equally well when going ahead of astern. Der total cost was £00,000, of which no less than U3,00 was for the engines.
As regards her speed and the efficiency of her machinery, the Triztericitelt did not do all that was expected o' her; she was neither more nor less successful than her sister ships, the Viper and Viet",', and they all three belonged to the slowest class of gun-boats.
As her machinery was mach more expensive than that of the others, nothing has as yet been done in the way of sdling to the number of hydraulic engines in the navy. They possess many advantages 'n regard to maneuvering the ship, but these am to a great extent also possessed by twin-screw engines, which can be made at a less cost; while some of the advantages origioally claimed for them, such as freedom from slip. haw not been realized in actual work. In such exceptional vessels us those of the Viper class, :t fair comparison of the merits cf the hydraulic propeller with those in common use can not be made. The net result of the experiments hitherto made is, that while the addition of one additional part to the nuraltinery between the engines and the actual propellers (which in this case arc the of water) is open to grave objections; still with a "turbine" less faulty in design. abol under more favorable eh-cultist:laces, the hydraulic propeller may be found useful in men-of-war. The Watertritrh, as well as her ma hydraulic sister ships, now ranks among the " klefficients" of the navy, having been pronounced useless for purposes of mot:ern warfare.