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March, 1910 of the dockyard. Three of these rise from the sea at Spithead, resting upon foundations built up from the bottom. These are armor plated. The entrance to the harbor is guarded by the bat- teries on the Portsmouth shore and several detached forts, while other batteries, some masked, and_ others defiantly showing their teeth occupy the high ground above the town. The Royal Powder Magazine at Tipnor> con- TAE MarRINE REVIEW tains the supply of gunpowder for His Majesty's forces in the Southern dis- trict. The principal magazine, however, is at Marchwood, near Southampton, ten or twelve miles away. Eastney Barracks, three miles from Portsmouth, are the headquarters of the Royal Ma- rine Artillery, and will hold 1,200 men. They are defended by strong earth- works, connected with a long stone coping. Elevator Dredge for Coast Harbor Work E have received from the Atlantic Equipment Co., New York City, some interesting particulars of a large below the low water level. This means that at high tide the dredging must be done at depth of about 50 ft. The Daly & Hannon Dredging Co., of Og- - Port Sipe or DENVER SHOWING CoNnTROoL House AND DISCHARGE CHUTE. elevator dredge, which they have equipped for work in Boston harbor. trations will be of particular interest to shipping men on the great lakes where the steamer Denver was well known. The use of elevator dredges in harbor work in the United States has been of a very restricted nature, although the Canadian government has used them more or less extensively on the St. Lawrence river and canal improvements. They have also been used in gold dredg- ing work in the western states and in Furope their use for harbor work is quite extensive. The Atlantic Equip- ment Co. says: The work in the entrance to Boston harbor covers a large area and excava- tion is required to a depth of 35 ft. The illus-_ densburg, N. Y., which has the contract for this work, had been, for many years, executing all their work with dipper 115 dredges, but in this case, on account of the depth and the exposure to rough weather, it was decided that a _ sea- worthy elevator dredge of large capac- ity would be more apt to give satisfac-. tory results. To meet these requirements, the dredg- ing machinery was installed in the steamer Denver, a heavily built wooden cargo steamer originally in service on - the Great Lakes. The contractors were fortunate in obtaining a vessel with oak frames and planking in such perfectly sound condition and of a quality not generally available. nowadays for ship- building. The Denver is self-propelling, with engines of 700 H. P., and is able to cross the ocean if necessary. The work of reconstructing the hull and in- stalling the dredging machinery was done by the Daly & Hannon Dredging Re on its own yards at Ogdensburg, The dredging machinery was built by the Atlantic Equipment Co., from the designs of A. W. Robinson, of Montreal. The form of the buckets is shown in the accompanying photo, which gives also some idea of their size. All parts subjected to heavy wear are of man- ganese steel. The capacity of each bucket is 1% cu. yds. and the bucket chain is driven ordinarily at a rate of 14 buckets per minute, so that the dredg- ing capacity with full buckets would be 1,100 cu. yds. per hour. This has been exceeded by more than 30 per cent for short periods in actual use. For driv- ing the bucket chain, a double tandem compound steeple engine is provided, with cylinders 12 in. and 16 in. by 18-in. stroke. This is, of course, entirely dis- tinct from the propelling engines. The ladder frame is of steel and is of sufficient length to work at a depth of 51 ft. The steel gantry for raising and lowering the digging end of the ladder can be seen just behind the pilot house. s The dredged material is discharged through a hopper and chute into scows of 1,800 cu. yds. capacity alongside. A sea-going tug is required in attendance to tow the scows to the dumping place and to advance from time to time the anchors which hold the mooring lines of the dredge. There are two bow and two stern lines from the dredge at- tached to heavy anchors placed at suit- able distances, the position of each of which is marked by a buoy. A contin- uous feed over the bottom is obtained by means of steam winches handling the mooring lines, and by a special ar- rangement these lines are held at some depth under the water so as not to interfere with the navigation of the tugs ELEVATOR DREDGE DENVER * AT WorK IN Boston HARBOR.