The term civil engineering has, therefore, two distinct meanings. In the widest and old est sense it includes all non-military branches of the engineering profession as it did a hun dred years ago; but in its narrower, and at the present day more correct, sense, it includes those branches of the profession which are left after the separation from the main stem of mechanical engineering, electrical engineering and metallurgical and mining engineering. But even in this restricted sense, what is properly included tinder the title of civil engineering re mains undoubtedly the widest in scope of the four great branches of the engineering pro fession, and in practising it a man must be come a specialist in some one or in several narrower fields. These fields may be enumer ated as follows: 1. The construction of railroads, now one of the largest fields both in number of men en gaged and in capital invested. The work of the civil engineer comprises the location and construction of the railroad, with all its vari ous structures, such as bridges and buildings, and also the maintenance of the railroad. The motive power is the field of the locomotive en gineer and is a branch of mechanical engi neerinz.
2. The construction of street and interur ban railways, a branch of civil engineering which touches on the field of electrical engi neering and may even be properly considered to belong to that field rather than to civil engi neering, inasmuch as all street and interurban railways are at the present time operated by electricity. The construction of the track and structures, however, aside from the motive power and its applications, is properly a branch of civil engineering.
3. The construction of highways and of city streets and pavements. This has always been an important field of engineering, for the high ways of a country, as Macaulay remarked, are a good index of its civilization; but with the advent of the modern automobile, the construc tion and maintenance of highways and of city streets have become of even greater import ance. In the application of various materials and bituminous products for the road surface, this branch of engineering touches on the field of chemistry.
4. The improvement of rivers and harbors, the construction of canals, of lighthouses and other works necessary for carrying on mari time trade and commerce.
These four fields constitute the field of transportation engineering.
5. Structural engineering, which comprises the construction of bridges, aqueducts, steel frames for buildings, retaining walls, and in deed all fixed structures with their foundations. This great field of engineering finds its applica tion in all of the other fields, for structures are requisite in all of them.
6. Hydraulic engineering, which includes the development of water powers and the con struction of dams and power plants up to the point at which the mechanical engineer is called upon to supply the motors.
7. Irrigation engineering which concerns it self with utilization of waters in agriculture, the diversion of water from streams and its ap plication to the land, with the various struc tures and appliances necessary for the purpose.
8. Surveying which is necessary in the lay ing out of works of all kinds in the field, but which constitutes a branch by itself known as land surveying when applied to the object of measuring and subdividing land, and which is known as topographical surveying when the object is to represent upon a map the surface configuration of the land, and which, further, when extended to the survey of very large areas in which the curvature of the earth must be taken into account, leads to the intricate and interesting problems of geodesy, or the measurement of the earth, and touches upon the field of terrestrial physics.
9. A great variety of problems due essen tially to the congregating together of people in cities and the necessity for conserving and protecting the public health. This includes works of water supply, sewerage, the disposal of wastes, the drainage of lands and of build ings and the heating and ventilating of build ings. The latter field has recently become the specialty of the heating and ventilating engi neer. The last group of subjects, involving the preservation of the health of communities, has within recent years become the special field of the new profession of sanitary engi neering (q.v.).
The above enumeration will make clear the vast extent of the field of what is still properly termed civil engineering, and will make it evi dent that this field touches at many points the other engineering professions and that the vari ous specialties themselves are in some cases closely related and yet divergent. In the con struction and operation of steam railroads and electric railways, the work of the civil engi neer comes in many ways into relation with that of the mechanical and with that of the electrical engineer. The same is true in the development of water powers, the construction of pumping stations for waterworks and the design of canal and harbor works and docks with the necessary operating machinery. In problems involving the construction of the foundations and steel frames for high build ings, the civil engineer comes into intimate re lations with the architect, with whom he must collaborate. The work of the sanitary engineer also comes in many ways into relation with economic, sociological and legal problems of great importance and difficulty.