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february, 1912 ance of the approaches and dock proper are, of course, straight. The steel' approach, =which is 317 ft. in length, is situated between the dock and the timber approach. It consists of four towers connected by plate girders as indicated in Fig. 3. It is widened at the top so as to accom- modate four tracks at the outer end. The girders between the towers are '63 ft. in length, while those over the towers are 32 ft. long., Hrom bent 1 to bent 5 there are four girders: be- tween bents 5 and 6 there are five 32-ft. girders and from bent 6 to the outer end of the approach there are THE MARINE REVIEW upper end of which slides in the slot ». the pressire of the ore in. the pockets cannot open the door so long as the dog shown in the illustration prevents the upper end of the link, L, from sliding freely in the slot. This dcg is controlled by the lever V, which extends up to the operating plat- form. When the lever is rotated the dog swings clear of the slot and the lower edge of the door is then free to move. The movement of the up- per edge of the door is controlled by the... yertical {slot 1. Eheo door i counterweighted, as indicated, so that it moves. easily. in operation as 53 Wis., built the foundations for the dock, and the steel structure was fabricated and erected by the Amer- ican Bridge Co. The work was done under the supervision of W. A. Clark, chief engineer of the Duluth & Iron Range railway. : New Dock at Superior. The Great Northern railway placed iil commission last season at Superior its new concrete ore dock equipped with 151 double ore pockets with a capacity of 325 tons each, making a total storage of 98,150 tons. This dock is assured of heavy tonnage for Fic... 1--A--Wooven Pitrnc For FounpaTIoN oF Presque Istz Ore Docx; B--Dertai or STEEL REINFoRCEMENT; C--Top or Docx BrErorE Laying PLanxinc; D--SipE View oF Docx, SHowiNG SLANT oF ORE POCKETS. six girders, this additional support at the outer end being necessary to take care of the four tracks. The framine of the tower is clearly indi- cated in Fig. 3, each bent being pro- vided with three columns. The col- umns rest on concrete pedestals sup- ported in turn by close-driven groups of piling. The dock proper is level, but the approach has a rising grade of 0.304 per cent towards the dock. The details of the chute and door are. chown in Fig. & ae Jatter is especially interesting. Its lower edge 'is guided by a link (L-Fig. 4.), the ' soon as the dog is released the door is drawn into the pocket P, leaving the full cross section of the chute free for the flow of the ore. When it is desired to cut off the flow the door is lowered and since the lower edge is guided it is forced into the stream of ore as it descends. The links and slots are so adjusted that the door describes a certain curve in raising and lowering with the effect that the resultant pressure from the flowing ore does not interfere with or prevent its crowding. Whitney Bros. &. Hill, of Superior, the next three years at least, as under the terms of the Hill ore lease the Steel Corporation's shipments- during the remainder of the life of the lease will run into many millions annually. Solid concrete columns are used to support the bins instead of the struc- tural steel posts which have been em- ployed heretofore. The walls of the bins, instead of being merely parti- tions, act as beams and carry the weight of the ore, the bin floors be- ing supported on I-beam purlins, ex- tending between-the supporting walls or partitions, as shown in Fig. 5.