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while the main air pumps, which are placed behind the condenser, and are of the vertical type, are also worked by their own engines. The connec- tion between the low-pressure cylin- der exhaust and the condenser is as shown, effected by one large function pipe. Steam for the main engine of the ship is supplied by twelve ordinary cylindrical multitubular boilers, de- signed to work at a pressure of 210 Ibs. per square inch, each having a large heating and fire grate surface. The smoke and waste gases are car- ried off by two funnels, each about 130 ft. high above the level of the fire bars. For the various services re- quired throughout the ship, there are, in addition to the main propelling en- gines, 24 auxiliary engines. A NEW HYDRAULIC DREDGE. The dredge illustrated herewith is a large and powerful machine built to the order of the commiss'oners of lincoln. Park,. Chicago, for. the pur- pose of filling in the new park exten- sion to the north of the present park. The. plan is to reclaim from Lake Michigan an area approximately 1,500 ft. wide by about a mile long by en- closing it with a stone revetment or breakwater and filling in behind: it with material taken from the bed of the lake. the breakwater lies in 18 ft. of water and the total volume of fill is about 4,000,000 cu. yds. The breakwater is now partly completed and is made of stone from the _ spoil-banks of the Chicago drainage canal. A fleet of large scows with several powerful tugs are employed to bring the stone trom the canal by way .of the Chi- cago river out into the lake and so to the site of the work. Fon much of the distance © "THE Marine REVIEW 35 HYDRAULIC DREDGE BUILT FOR THE COMMISSIONERS OF LINCOLN PARK, CHICAGO. The conditions surrounding the dredging and filling of this work were dificult and peculiar. Not only was the locality in deep water and ex- posed to the storms of Lake Michi- gan, which often rise with suddenness and. severity, but the - soil. to be dredged consisted of the tough blue clay which underlies the Chicago area, compacted by the storms of the HYDRAULIC DREDGE BUILT FOR THE COMMISSIONERS OF LINCOLN PARK, CHICAGO. lake and mixed with more or less gravel and stones. . The ordinary hydraulic dredge as used on the lakes would therefore be unsuitable first because of wunsea- worthiness, and secondly, because it could only deal effectively with soft material. The usual floating pipe-line connected by rubber . sleeves and mounted on a number of small scows or floats would be put out of business with every wind storm or irretrievably wrecked. The superior economy of the hy- draulic process of dredging and filling if it could be successfully applied led Francis. [. Simmons, president, and R. H. Warder, secretary, to pursue the subject further to see if these dif- ficulties could be overcome, and they therefore commissioned A. W. Rob- inson, member American Society of Civil Engineering, to examine and re- port on the ground and if possible to design a dredge that could cope with the difficult conditions presented. Mr. Robinson had previously designed and built several large hydraulic dredges notably the Tarte which is employed in dredging clay from the bed of Lake St. Peter in the River St. Law-