[Sidenote: Several features of our city governments.] At the present day American municipal governments are for the most part constructed on the same general plan, though with many variations in detail. There is an executive department, with the mayor at its head. The mayor is elected voters of the city, and holds office generally for one year, but sometimes for two or three years, and in St. Louis and Philadelphia even for four years. Under the mayor are various heads of departments,--street commissioners, assessors, overseers of the poor, etc.,--sometimes elected by the citizens, sometimes appointed by the mayor or the city council. This city council Is a legislative body, usually consisting of two chambers, the aldermen and the common council, elected by the citizens; but in many small cities, and a few of the largest,--such as New York, Brooklyn, Chicago, and San Francisco,--there is but one such chamber. Then there are city judges, sometimes appointed by the governor of the state, to serve for life or during good behaviour, but usually elected by the citizens for short terms. All appropriations of money for city purposes are made by the city council; and as a general rule this council has some control over the heads of executive departments, which it exercises through committees. Thus there may be a committee upon streets, upon public buildings, upon parks or almshouses or whatever the municipal government is concerned with. The head of a department is more or less dependent upon his committee, and in practice this is found to divide and weaken responsibility. The heads of departments are apt to be independent of one another, and to owe no allegiance in common to any one. The mayor, when he appoints them, usually does so subject to the approval, of the city council or of one branch of it. The mayor is usually not a member of the city council, but can veto its enactments, which however can be passed over his veto by a two thirds majority.