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pe MARINE REVinws 7 ae Pneumatic Steering Gear of U. S, Monitor Terror.* _ The pneumatic steering gear is simple and powerful. Two athwart- ship cylinders, whose pistons are attached to the same heavy piston-rod, are firmly secured to castings built into the ship; the round stern of the Terror being peculiarly favorable to the athwartship arrangement, At mid-length, the piston-rod carries a slotted head, the brassés of which permit the sliding of the tiller as its angularity changes. The two cylin- ders are respectively to starboard and to port, and their outboard ends are utilized as motors. The common piston-rod is so large that only a small area 1S leit on the inboard face of each piston. The inboard ends of the cylinders are connected by a pipe in which there is a controlling piston valve operated by the same mechanism that admits air to and exhausts it from the outboard ends of the cylinders, _The distribution of air is effected by a simple slide valve receiving its motion from a "float lever," one end of which is controlled by an arm projecting from the rudder head. The float lever receives its initial motion from a threaded spindle working in a nut on the lever. The spindle can be revolved in various ways, to be mentioned hereafter. When the distributing slide valve 1s in mid-position, so also is the controlling valve, the latter preventing any exchange of air between the inboard ends of the cylinders. Any rotation of the threaded spindle moves both the distributing valve and the controlling valve, one valve supplying the power and the other relieving the elastic lock. The threaded spindle which operates the float lever lies in a fore- and-aft direction and carries various clutches, all but one of which engage with sprocket wheels. At the end of the spindle is a clutch which engages with an electric motor geared down by worm gearing. The wires from the motor lead to the rheostats at the steering stations in each turret and in the pilot house. The same stations are provided with small wheels which give motion to small wire ropes led to drums in the steering room, Each drum has its separate sprocket-chain connection to a screw spindle of the steering gear. So long as there is a supply of air, the principle of the float lever insures the motion of the tiller in obedience to that of the screw spindle. Each steering wheel is provided with a geared index, which acts as a tell-tale or indicator of the rudder's motion or, rather, of the motion which the rudder should have as a result of the motion imparted to the screw spindle of the float lever. It is proposed to connect the tell-tale directly to the rudder post. The officer of each gun has under his feet, just above the central column, a circular index with two concentric circles, one showing the amount of rotation of the turret, the other the helm angle, The following table indicates the general dimensions and other data: Diameter of steering pistons, 14 inches; stroke, hard over to hard over, 5 feet 10 inches; lap of slide valve, nothing; exhaust lap, 1-32 inch; least tiller radius, 4 feet; least time, hard over to hard over, 120 pounds air pres- sure, at dock, 4 seconds; area of rudder, 81.2 square feet; width of rudder, unbalanced, 7 feet 9 inches; diameter of piping, 1% inches; minimum air pressure that has been used if steering in smooth sea, 30 pounds per square inch; diameter of drum ropes, 34 inch; least pressure to move steering gear at dock, 5 pounds per square inch. -- During the service of the Terror, since Feb. 13, 1897, the vessel has been steered only by the pneumatic machinery, either directly or by the electric control of the pneumatic valve of the steering engine. The pres- sure of 125 pounds per square inch in the steering cylinders is maintained by one of the main air-compressing engines running four revolutions per minute, the ship being under way at sea and air being drawn for steering only. The power of the steering cylinders is apparently excessive, owing to design for a speed of 12 knots, whereas the highest speed obtained with full power was but 9.5 knots. ; : : A very quick helm is required in this ship, but, while the full helm angle is frequently used, it has not been .ound necessary to maintain, for steering, a pressure above 60 pounds, which gives an ample reserve of power. The economy of the plant is shown by the fact that an auxiliary compressing engine, installed for steering only, and weighing but 1,100 pounds, can maintain an air pressure of 125 pounds in the cylinders while the ship is manceuvering, and can furnish for steering at sea sufficient pres- sure at a much reduced number of revolutions. Changing to electric valve control is accomplished by simple means readily and quickly, leaving nothing to be desired in that respect. : d Steering either in the chart house or in the forward turret has prove easy by the pneumatic wheel or by electric control, The transmission from the steering wheels in the chart house and turret to the pneumatic valve is not attended by great friction, the leads being good and compara- tively short. The valve ropes from the steering engine to the nea! wheel are run over and around ball-bearing sheaves, which reduce the fric- tion to at least 50 per cent. less than the ordinary method. Air leaks - about the steering cylinders are quickly discovered and easily ee In the service of this vessel but one considerable leak has occurred as and it was remedied by renewing the packing. This is the only repalt Ww ce has been made to the steering engine during a years service. eee does not get out of order, and does its work with certainty and e ener Very little lubrication is required, and the engine and ee S henoaee always free from dirt, heat, moisture, noise and shock. een Pease cers who tested the apparatus expressed the opinion t at i he baa: a engine is well adapted to use for steering ships. ee af ae a ee accurate in operation, free from accidents and. brea ee a ay MEAG Sesses the valuable quality of BEE an elastic air lock tor ever in hich it is moved. ae : ae edeierme the minimum size of air compressor required ee the Terror, observations were taken of the helm ee in pee St eit nor's island into the East river. The position of the he im ue ae ee five seconds for fifteen minutes, and the results uene at ae the pneu- helm of 68° per minute. This is equivalent to one . Oe Rees Matic cylinder, whose capacity is 6 cubic iRerelig the as Ae soar eae peated observations that when the ship is steaming i ory 125 pounds to 8 knots, and there is a pressure in Te eee ist n from amidships per square inch, the helm can be moved by the aus aes pei ares hard Pemard over (84°). in four seagaey ae bo aoe was at the dock over the other side (68°) in seven seconds. W na') in Pa ee eae ith the helm was put from hard over to hard over ( the helm through 68° 125 pounds pressure. The same speed of moving ae d at the fifth general meeting of the Marine feigineers, held in New York, Nov. 11 and 12, 1897. Society of Naval Architects and with a pressure of 125 pounds per square inch down to fifty pounds, was maintained in the same length of. time, four seconds. The rudder could have been moved faster but for the limit of the man's speed in turning the hand wheel for moving the valve in tiller-room. There is considerable gain in the helm speed in the Terror, as the rudder can be started and stopped very quickly without danger, owing to the air cushion in the cylinder. The experiments showed that the helm followed the valve wheel instantly, without shock or noise. The electric motor for moving the valve and valve ropes used from 8 to 15 amperes of current at 80 volts. When: the valve was moved slowly it required from 6 to 10 amperes. This gear was built and installed on the Terror by the Pneumatic Gun Carriage:& Power Co. of Washington, D. C. History of Our Navy. Messrs. Charles Scribner's Sons have given us what is on the whole the best history of the United States navy thus far published. Its author, John R. Spears, possesses special qualifications for his. work. He spent three years at the naval academy, resigning July 31, 1866, and his academy experience was during the closing years of the civil war, when the whole country was alive with the stories of naval adventure. He is a thorough master of the nomenclature of the sea, and, as the author of "The Port of Missing Ships," "The Gold Diggings of Cape Horn," etc., he has learned the art of reaching the ears of people by effective writing. The great fault with so many works of historic research is that they are unreadable, and nothing less than a stern sense of professional obligation or zeal for his- torical instruction can persuade one to devote to them his hours of relax- ation. There are no chapters in our national history so exciting and en-. tertaining in themselves as those that record the story of the battles and adventures of our warriors afloat. The dullest of writers cannot make them altogether uninteresting, and to one who understands the art of pic- turesque and effective writing they furnish material for vivid description that equals imaginative writing in absorbing interest. Mr. Spears does. not appear to have attempted much in the way of original research, but he takes the familiar facts of our naval history and presents them so effect- ively that they derive fresh interest from his skilful handling. His narra- tive is warm with the steady glow of an ardent patriotism, and no one who reads it can fail to have awakened in his heart a more earnest love of country and a surer resolution to sacrifice all, if need be, in defense of his native land and for the honor of the flag. Hence these are admirable volumes to place within reach of our novitiate heroes. That they will soon be in the library of every man-of-war in our service we do not doubt, and no public or private library that takes note of heroic literature can be complete without them, for their study will inspire young and old alike with the spirit of self-sacrificing patriotism. We may thank God and take courage for the future of our country when we find Mr. Spears de- claring, as he does, with undoubted truth, in speaking of our early naval heroes, "that every class graduated from the naval academy at Annapolis -- contains men of equal bravery and resources--men needing only the op- portunity to show their mettle." Mr. Spear's history is handsomely printed and interesting illustrations swarm through the volumes, num- bering hundreds in all. A number of full-page illustrations of engage- ments during the civil war are copied from paintings by Adm. Henry Walke, U.S. N., one of the most gallant heroes of that war--Army and Navy Journal. Northwest Wheat Crop. Advices from the northwest spring wheat states are that the wheat crop there has been marketed more rapidly than usual, it peing estimated that 53 per cent. of the yield had been stored in second hands by Nov. 15, as compared with about 43 per cent. one year ago and in like portions of preceding seasons. It is estimated that about 100,000,000 bushels of wheat are to be shipped to Minneapolis and Duluth from this crop, of which, therefore, about 53,000,000 bushels have been received. Should this esti- mate prove true, there are still 47,000,000 bushels of spring wheat to go forward, of which 7,000,000 bushels are already out of farmers' hands, scat- tered along various lines of northwestern railways, leaving 40,000,000 ~ bushels, nominally, in farmers' hands, a large portion of which, of course, sooner or later, will have to be marketed. There are several careful ob- servers in the northwest who think that these figures are too small, but as the people living in the region referred to are constitutional bulls on wheat, any tendency to magnify the.size of the crop there must be regarded as conservative.--Bradstreets. Following close upon the building of an experimental tank for trials of ships' models at the Washington navy yard, comes the announcement from Ithaca, N. Y., that there is in process of construction at Cornell University a general hydraulic laboratory, to be under the charge of the College of Civil Engineering. One feature of this laboratory will be an experimental tank or canal about 350 feet long by 16 feet wide and 10 feet deep. While this tank is a part of a general hydraulic laboratory installed in charge of the College of Civil Engineering, it is expected that, through the kindness of the director of the college, it will be available for distinct- ively marine work as well. It has long been the desire of Prof. W. F. Durand of the College of Naval Architecture and Marine Engineering at Cornell to bring about in this country the construction of an experimental tank that would not be confined to naval uses or controlled by private en- . terprise. His idea was to take full advantage with such a tank of the great opportunities for general advancement of the science of ship build- ing. It would seem that Prof. Durand's wishes are about to be gvatified to a large extent in the construction of these two basins, with their ac- companying scientific apparatus. The results of investigations to be made at Washington and Ithaca will not be buried in secrecy. The Brown Hoisting & Conveying Machine Co. of Cleveland has contracts in hand for half a dozen plants of their special kind to be applied - to iron furnaces, steel works and docks in Germany, Russia, Japan and Central America. They are erecting for Fried. Krupp & Sons blast fur- nace machinery similar to that applied to the big blast furnaces of the Carnegie company. "