ENGINEERING (from the French word engin) is properly the art of constructing and using engines or machines ; but the term is also applied to that of executing such works as are the objects of civil and military archi tecture, in which machinery is in general ex tensively employed.
A distinction has long been made between the civil and military engineer; and since every thing relating to the service of artillery is now confided to a particular corps, the duty of the military engineer may be said to corn. prebend the construction of fortifications, both permanent and temporary, including the trenches and batteries required in besieging places ; also of barracks, magazines, and other works connected with warlike affairs.
The profession of the civil engineer com. prebends the design and execution of every great work by which commerce and the prac tice of the useful arts may be facilitated. Thus, in creating or improving the communications of a country, he would be called upon to form a road through hills, or over valleys or rivers, or to excavate a canal in connection with the waters by which it may be supplied, and to build the locks for retaining the surface at different levels, in different places, when the inequalities of the ground are considerable. He raises embankments to resist the encroach ments of the sea or to reclaim the land which it may have covered, and dams to break the force of its waves at the mouths of natural harbours. He renders rivers navigable when their course is obstructed by rocks or banks ; he forms docks or artificial harbours where ships may remain in security ; he is required to penetrate by mines to vast depths for the purpose of seeking the mineral treasures con tained within the bosom of tho earth ; and the formation of iron roads or railways is now a most important branch of the profession. Such are the occupations of this class of men ; and it is necessary to observe that they fre quently, in addition, practise the avocation of the machinist in executing the presses, mills, looms, and other great machines employed in the arts and manufactures ; particularly in constructing steam-engines and the apparatus by which they are rendered available for giving motion to ships, carriages, or machinery.
In France the title of engineer is extended to persons who are employed for the public service in trigonometrical surveying in the in terior of a country or on the coasts, and in the practice of naval architecture. The French have thus a corps of ingenieurs geographes, of ingenieurs d'hydrographie, and of ingenieurs de marine.
Of the national works executed by the an cients, and which are to be considered as pro perly falling within the province of the engi neer, one of the first of which we have any intimation is the canal uniting the Red Sea and the Nile, which, according to Pliny, was begun by Sesostris, or, according to Herodotus, by Necos, the son of Psammetichus, and finished by Darius the First. The canal of Xerxes across the isthmus of the peninsula of Athos is another example of works of this kind. The introduction of arches in works of magnitude may be said to have constituted an epoch in the profession of the architectural engineer, since the idea of giving to blocks of stone a form which would enable them to sustain themselves in balanced rest by their mutual pressures, the discovery of the means of arranging them on a curve surface, and the determination of the magnitudes of the piers or abutments so that the lateral pressure of the vault might be adequately resisted, imply a higher degree of intellectual power than is exhibited in covering a space with a horizontal roof. The Cloaca Maxima [CLoac.,E] at Room is probably the most ancient example in Eu rope of this scientific construction. The dome of the Pantheon, and the various arches of the Therma3 and of other public buildings, both at Rome and in the provinces, such as aqueducts and bridges, attest the grandeur of design, combined with purposes of public utility, which characterised the architects who lived under the early emperors, Previously to the commencement of the eighteenth century, the most celebrated prac tical engineers were Brunelleschi, who built the dome of St. Mary at Florence ; Peruzzi, San Gallo, and Michel Angelo, who executed that of St. Peter at Rome ; San Micheli, the supposed inventor of the bastion system of fortification ; and to those may be added Sir Christopher Wren, the architect of St. Paul's Cathedral in London.