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MARINE REVIEW. 7: The Grain Outlook, If estimates regarding the northwestern grain crop are correct, it would seem that vessel owners are certain of profitable lake freights from the head of Lake Superior before the present season is at an end. It is certain that iron mines at the head of the lakes, nearly all of which are producing bessemer ore, will be worked to their utmost capacity throughout the season. Within the past few days lumber shippers have advanced rates, in order to attract tonnage to Duluth and Ashland. It was estimated early in the season that the shipments of lumber from all Lake Superior points would be full 100,000,000 more than they were in 1894, but now with lumber sales very active it is found that the St. Mary's Falls canal records show an increase to August 1 of only 31,214,000 feet. Thus in advance of any movement of grain, the demand for vessels to carry ore and lumber is constantly exceeding the supply, and it is well known also that coal shipments are short of what they should be, in view of the large quantity of coal that will be needed tocare fora big grain crop. All estimates place the wheat crop of Minnesota, the Dakotas and Manitoba at full 200,000,000 bushels, of which Manitoba will produce some 25,000,000 bushels. In 1891 Minnesota and the Dakotas harvested 160,000,000 bushels. The average since wheat became a leading crop has been about 115,000,000 bushels. The mills of Minneapolis and Duluth consume not far from 55,000,000 bushels, and at least 25,000,000 more will be needed for seed and bread. This will leave for shipment east not less than 90,000,000 bushels, in all probability. Never has there been shipped from Duluth more than 45,000,000 bushels on asinglecrop. Itis expected that Minneapolis will ship largely by rail to mills in the south and west, but the water shipments from Duluth will far exceed anything known: An increased movement of flour is, of course, assured also. An Immense Dry Dock: Some very big dry docks have been built in this country of late years, and others now under way, notably those being built by the navy department, are of large proportions, but it is doubtful if any of these projects will prove equal to the big dry dock just completed at Southamp- ton, England, for docking Atlantic passenger ships like the St. Louis, Paris and New York. The Southampton dock was constructed in sub- merged mud land and the time taken up in the work was only two and a half years. The dock hasa length on the floor of 750 feet. The width at sill level is 87 feet 6 inches, and at the cope 112 feet. At high water, ordinary spring tides, the depth of water over the sill in the centre is 35 feet, but as the sill has an invert, with a radius of 194 feet, the depth at the side is reduced by nearly 5 feet. A minimum depth of 31 feet is, however, more than sufficient, in view of the fact thatin all harbors the present limit is 27 feet or 28 feet. There will be within the dock a depth of 29 feet over the top of the keel blocks at ordinary low tides, and 32 feet 6 inches with spring tides. The width of the dock itself is 87 feet 1 inch at the bottom, and 112 feet at the top of the altars. The first operation in the work of construction was the enclosing of an immense area of reclaimed mud land with a chalk embankment 18 to 20 feet wide. A grip was first dredged in the mud down to the peat. This grip was 12 feet wide at bottom, and the chalk being tipped in, it formed a good key for the embankment, which was raised to a level 6 feet above high water at spring tides. The slopes exposed to the wash of the sea were stone-pitched, all parts being carefully sealed with exca- vated material. Sluices were put in through the bank, but were not re- quired. The area wasthen pumped dry. About 1,200 men were continu- ally employed onthe work and the value of the contractors' plant is estimated at $450,000. The plant included eight locomotive engines, eight portable engines, forty steam cranes, eighteen steam pile engines, five tug boats, two steam launches, two steam hoppers, four steam dredgers, twenty-five barges, twenty-three steam pumps, 500 contractors' wagons, and 900 tons of rails used in the temporary railways. The extent of material used shows the amount of work done. Of chalk 470,000 cubic yards were used. The material excavated for the dock totalled 230,000 cubic yards, and of concrete there was used 84,000 tons of eight to one and 15,000 tons of richer kinds. Of granite 45,000 cubic feet were worked into the dock. Beyond the dry dock works, in the other reclamation and wharf works, there were 30,000 cubic yards of stuff excavated, and 1,063,000 tons of dredging. There were used on the wharves 14,000 cubic feet of timber, 251,000 cubic feet of pitch pine and other timber, 23,000 tons of Portland cement, and 142 cubic yards of ballast. The dock is built of Portland cement concrete faced with bricks, and the brickwork itself is faced with blue bricks. The altars, coping, cais- son stop, and sluice faces are all made of Cornish granite. There are three flights of steps from the surface to the floor of the dock, which when dry has the appearance of an immense space considerably greater than can be filled by the largest steamer yet constructed. The emptying of the dock is performed by two 18-inch direct acting pumps, which are capable of drawing off the water in from one and a half to two hours. The discharge of water is at the rate of 500 tons per minute. The dock contains, when filled, sixteen and a quarter millions of gallons. Six boilers, 30 feet long and 7 feet 6 inches diameter, supply steam for pump- ing machinery, cranes, capstans, etc. One traveling crane, worked in connection with the dock is capable of lifting 30 tons. _ In the construction of the ship caisson at the entrance to the dock 450 tons of iron were used, and it is ballasted with about 460 tons of cast- iron cantiledge. It was built near the dock, and, after completion, was launched forward and lowered into position. The caisson is 95 feet long on deck, and has an extreme breadth of 25 feet and depth of 45 feet. It is raised and lowered in the water by means of valves, and when it is buo- yant with the water inside the dock, on the same level as that outside, it is floated into a recess provided for it, and thus any vessel may pass in or out of the dock. Peculiar Engines in a Side-Wheel Steamer. As light draft side-wheel steamers are becoming more numerous on the lakes each year, a description of engines recently fitted to a boat of this kind built by Laird Bros. of Birkenhead, England, will be found in- teresting. The boat is 220 feet long between perpendiculars, with a beam of 26 feet and a depth of but about 12 feet. The engines are noteworthy for the reason that the problem was to get about 2,500 horse power into the shallow hull with the least possible weight and with the least avail- able space. This has been effected by combining inclined oscillating engines. There are two diagonal high pressure cylinders, 28% inches diameter, and two low pressure vertical oscillating cylinders, 50 inches in diameter, the stroke of all four pistons being 5 feet. There are two cranks only, each crank being driven by one inclined and one oscillating cylinder. The in- termediate shaft is cut in two and fitted witha coupling clutch. When this is thrown out of gear one paddle-wheel can go ahead and the other astern The coupling consists of a disc,in which area number of cylindrical holes keyed on the board crank shaft, and a similar disc into which are screwed an equal number of round steel pins, which slides ona fast feather in the starboard shaft. When the pins enter the holes both en- gines run together. But they can run equally well without this coupling, which is only rendered necessary to prevent racing when the ship in rolling buries one wheel, lifting the other out of the water. Each pair of cylinders is provided with its own surface condenser in the wing, and supplied with cooling water by centrifugal pumps. There are two- single-acting vertical air pumps, one for each engine, worked with the bilge and feed pumps by bell crank levers off the diagonal crosshead. The shaft and piston rods are of steel. The high pressure cylinder has piston valves and the low pressure slide valves, all worked by link motion. Steam is supplied by two large locomotive boilers, which closely resemble railway boilers in design. Each boiler has, however, two distinct fire boxes, and the firing holes come down to the level of the grate bars to facilitate cleaning fires. The pressure is 130 pounds. The box end of the boilers, which stand side by side fore and aft in the boat, are next the crank shaft. There is atransverse bunker, which divides the engine from the boiler room, with a passageway amidships through the bunker. The funnel is a very flat ellipse in cross section, and double; that is to say, there isaninner and outer funnel. Draftis obtained by the aid of alarge fanin the base ofthe funnel. The fanis about 4 feet in diameter, and is driven ata moderate velocity by a vertical single- cylinder engine in the port side of the fidley house, on the level of the main deck, The uptakes of the boilers open into the eye of the fan on the port and starboard, the fan shaft running athwartships. The shaft is cased in a tube several inches larger. This tube opens inside into the fan, so that a current of cold airis drawn continually between the tube and the shaft. This keeps the shaft quite cool, and no difficulty at all has been experienced with the bearings. The draught produced is yery good. Ata moderate speed it is equal to 1 inch of water in the asphits, The stokehold is very cool, and there is a total absence of dirt and dust, necessarily concomitants of the closed stokehold system. The vessel has shown a speed of 184 knots. Another steamer, the C, W. Elphicke, drawing only 14 feet of water, has struck the obstruction in Lake Erie near Pelee point light which _ was found recently by the J. C. Lockwood. Captains of both vessels give about the same location for the obstruction--S. E. by S. 44 miles from Pelee point light. It is in Canadian water, and on this account the United States light-house officials will probably have nothing to do with putting a buoy onit. The hydrographic office has been notified of the dis- covery, but this service can not, of course, do anything more than to give publicity to the fact that such an obstruction has been found, AN EXCELLENT LIBRARY FOR A MARINE ENGINEER, CHEAP--KEY TO ENGINEERING; WHAT AN ENGINEER SHOULD KNOW ABOUT ELEC- TRICITY; ENGINEERS' CATECHISM. ANY ONE OF THESE ARE WORTH A DOLLAR, BUT ALL THREE CAN BE HAD FOR $1. SEND TO THE MA- RINE REVIEW, 516 PERRY-PAYNE BUILDING, CLEVELAND, 0. MONEY REFUNDED IF NOT SATISFACTORY.