A bridge is built. If it is built to meet an insistent public demand, if it solves a traffic problem or a transportation problem otherwise insoluble, if, in short, it is even more necessary to the taxpayers collectively than the things for which they would have individually spent their money if it had not been taxed away from them, there can be no objection. But a bridge built primarily “to provide employment” is a different kind of bridge. When providing employment becomes the end, need becomes a subordinate consideration.