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M A R I N E broken stone, concrete is placed to a depth of 5% ft., and with this for a foundation the upper portion of the dam is con- structed. About 1,400 piles will be used in the erection of the dam. In the construction of the lock, the entire area was dredged out a depth of 9 ft. and a coffer dam the size of the lock was built. Openings were left in the lower end to permit pile driver boats to enter and the coffer dam was pumped out, sufficient water being permitted to remain so that the pile driver boats could float. Over this entire area, covering 425 by 170 ft., piles were driven 4 ft. apart and under the lock walls at a distance of only 3 ft. About 5,300 piles were used, ranging in lengths from 15 to 22 ft. After the piles were driven the coffer dam was pumped out and the piles cut off to their desired height. Four lines of sheet piling were then driven for the protection of the lock foundations, consisting of three 4-in. planks. The piling was then 'filled in with broken stone and on top of this the concrete was placed. The lock walls were then built on this bed of concrete as a foun- dation. The three walls are 30 ft. high, the land wall being stepped with a width of 16 ft. at its base and 514 ft. on top; the middle wall is 20 feet wide with vertical sides and the river wall has a width of 16 ft. 4 in. at its base and is 7 ft. wide on top. At the gate recesses the walls are 18 ft. wide at the base and 14 ft. on top. As stated before the lock has two chambers each 56 ft. wide and the land and river walls are each 469 ft. long, while the middle wall has a length of 522 ft. The river chamber is to be provided with an inter- mediate gate for the locking of small craft. The lock walls are already completed. Miter gates will be provided of steel construction, the upper gates to be 21% by 30 ft. 9 in. and the lower gates 30 ft. 9 in. by 27% ft. The gates will have a miter angle of 20 degrees and will weigh approximately 30 tons each. The gates will be operated by chains leading to drums operated by com- pressed air from the main power house on the river bank, the chains connecting with the bottoms of the gates. Each gate will be opened and closed by one compressed air engine. Ample facilities for filling the locks have been provided and it is estimated that this can be done in about five minutes. The river lock will be filled by two filling conduits through the river wall above the dam 6 by 6 ft. in size and one conduit 7 by 8 ft. which takes in water in the upper gate recess in the river wall and distributes water through four openings each 5 by 6 ft. below the upper miter sill. The land lock will be filled by one conduit through the upper guard wall 7 by 8 ft. in size with four openings through the sill, and one 7 by 8 ft. conduit leading from the gate recess through the land wall to two 6 by 6 ft. openings into the land chamber. For emptying the land chamber two 7 by 8 ft. conduits will take the water from the lower gate recesses around and below the lower gate recesses into the lower pool. The river lock will empty through two 7 by 8 ft. conduits through the river wall into the lower pool. For emptying the intermediate lock in the river chamber one 6 by 6 ft. conduit will be used emptying around the intermediate gate through the river wall into the lower pool. The work is -in 'charge of Major W. L. Sibert, corps of United States engineers with Col. T. P. Roberts as assistant engineer. The field work is in direct charge of John B. Dim- mick. The Dravo Contracting .Co., Pittsburg, was awarded the contract for erecting the lock and the American Bridge Co. the contract for building the gates, while the construc- tion of the dam is being done by the government by day labor. * Capt. Henry C. McCallum of Detroit has bought the steam- er R. J. Hackett and schooner Wm. McGregor from the Vul- can Transportation Co. of Detroit. It is understood that Capt. McGregor will fit out the steamer with deck engine and der- ricks for handling package freight. R EB V 1 8 THE FUTURE OF THE OHIO RIVER VALLEY By John F. Dravo, The Ohio river ranks as one of the great rivers of the United States, and with its connecting valleys and_ side streams forms a system of waterways covering and _ inter- secting many thousand square miles of territory rich in the promise of coming population and wealth. Within the do- main of these waters are vast mineral deposits and num- erous industrial plants demanding corresponding transporta- tion facilities, which at the present time, as in the past, are only available during irregular and limited periods of the year, brought about by the intermitting navigable condi- tions of the river ranging from flood height to extreme low tides, reducing commercial use to uncertain and limited periods of the year. Transportation, subject to such ad- verse conditions, must. necessarily fail to meet industrial wants and consequently fail to develop prosperous trade con- ditions. If this great waterway has not measured up to re- quirements of a possible tonnage, the reason will be found CAPT. JOHN. ¥.. DRAVO, in the failure of the government to co-operate with nature in utilizing natural forces in the form of great floods sweep- ing in rushing torrents from.mountain to gulf, helpful for a brief period in the movement of commercial tonnage. The construction of the Panama canal will create such an imperious demand for the connection of inland carriage with ocean highways as to insure.the necessary appropriations for the completion of a system of reliable water tonnage ship- ments from headwaters to the Gulf of Mexico, ample enough to meet the commercial wants of the great valleys. The demand for the products of mill and mine in the Mississippi valley and the limited time of possible delivery resulted in the development of a system of water carriage out- classing all other forms for capacity and cheapness on land, sea or ocean, known as the towing system, which consists of a number of loaded crafts hitched in compact forms to