And Higher Still

Although the steel skeleton greatly increased the number of floors for a period of ten to fifteen years, the elevator machinery itself suddenly seemed to be the limiting factor. The hydraulic technique imposed a limit of eighteen to twenty floors. To build higher would be entirely uneconomic due to the slowness of elevators and the excessive space occupied by them and their voluminous machinery. In the end, it was electrically powered elevators with their more modest space requirements and improved speed that cleared the way for almost limitless increases in building height.