---------------------+------------------------+---------------- | | Drainage Area, Place. | River. | Square Miles. ---------------------+------------------------+---------------- New Orleans, La. | Mississippi | 1,261,000 St. Louis, Mo. | Mississippi | 700,000 St. Petersburg | Neva | 108,000 Louisville, Ky. | Ohio | 90,000 Rock Island, Ill. | Mississippi | 88,000 Budapest | Danube | 79,000 Cincinnati, O. | Ohio | 75,700 Dordrecht | Maas | 68,000 Rotterdam | Maas | 68,000 Schiedam | Maas | 68,000 Altona | Elbe | 52,000 Hamburg | Elbe | 52,000 Stettin | Oder | 40,000 Magdeburg | Elbe | 36,000 Warsaw | Weichsel | 34,000 Odessa | Dneister | 26,000 Worms | Rhine | 25,000 Grand Forks, N. Dak. | Red River of the North | 22,000 Frankfort on Oder | Oder | 21,000 Bremen | Weser | 15,000 Suburbs of Paris | Seine | 12,000 Poughkeepsie, N. Y. | Hudson | 11,600 Pittsburg, Penn. | Allegheny | 11,400 Posen | Wartha | 9,400 Hudson, N. Y. | Hudson | 9,200 Albany, N. Y. | Hudson | 8,200 Breslau | Oder | 8,200 Brieg | Oder | 7,500 Lawrence, Mass. | Merrimac | 4,634 Stuttgart | Neckar | 1,660 Brunswick | Ocker | 650 Somersworth, N. H. | Salmon | 171 ---------------------+------------------------+---------------- PRELIMINARY PROCESSES TO REMOVE MUD. With both sand and mechanical filtration the difficulty and expense of treatment of a water increase nearly in direct proportion to the turbidity of the water as applied to the filter; and it is thus highly important to secure a water for filtration with as little turbidity as possible, and thus to develop to their economical limits the preliminary processes for the removal of mud. One of the most important of these processes is the use of reservoirs.