☞ In a comprehensive sense, engineering includes architecture as a mechanical art, in distinction from architecture as a fine art. It was formerly divided into military engineering, which is the art of designing and constructing offensive and defensive works, and civil engineering, in a broad sense, as relating to other kinds of public works, machinery, etc. – , in modern usage, is strictly the art of planning, laying out, and constructing fixed public works, such as railroads, highways, canals, aqueducts, water works, bridges, lighthouses, docks, embankments, breakwaters, dams, tunnels, etc. – relates to machinery, such as steam engines, machine tools, mill work, etc. – deals with the excavation and working of mines, and the extraction of metals from their ores, etc. Engineering is further divided into steam engineering, gas engineering, agricultural engineering, topographical engineering, electrical engineering, etc.