SIEGE, literally a sitting down. When the assault of a fortified place would be too hazardous and costly and its reduction by blockade too slow, recourse is had to the "regular siege or systematic attack." In order to cross the open ground swept by the fire of the fortress with as little loss as possible the besieger makes use of sunken roads or trenches. The revet ments having been breached by his artil lery or mines, he continues these roads through the breaches into the place. To prevent these "approaches" being enfi laded by the guns of the fortress they are made at first in zigzags; the prolongations of which are directed so as to clear the works of the fronts attacked, and, when a direct advance becomes necessary, they are provided with traverses at short intervals, or "blinded sap" is used—i.e., a trench covered in with timber and earth. Two or three such lines of approach are used. To protect and connect them lateral trenches are formed from which large bodies of troops can fire upon any sortie that may be made. These are termed "parallels," being parallel to the general front of the parts attacked.
The ancients used to surround the place attacked with a high bank of earth, called a "line of circumvallation" and protected themselves against attack from the out side by another called a "line of contra vallation," and a similar arrangement was in vogue till the middle of the 19th century. Now a covering field army is employed, which by its greater mobility, is able to meet the relieving army many miles from the besieging force, and a chain of fortified localities takes the place of the continuous line of circumvallation. In order that a siege may be safely under taken the strength of the besieger should be about four times that of the garrison. In 1870 Strasburg, with a garrison of 20,000, was captured by a besieging force of 60,000 strong. Metz was starved into surrender, the presence of so many men (some 170,000) besides the proper garri son only hastening that result.
The "siege parks," or main depots, for the artillery and engineer trains must be out of range of the enemy's guns, con taining as they do powder, ammunition, guns, and warlike stores of all descrip tions. The batteries necessary are "en
filade" batteries, placed on the prolonga tions of all the important works attacked; "counter" batteries, to overcome the fire of the works bearing upon the field of attack; "mortar" and "howitzer" bat teries, to search by high angle fire the interior of all the works attacked; and "breaching" batteries, to breach by curved fire the scarps and flanking casements. Light pieces, such as the seven-pounder mountain guns and machine guns, are placed in the second and third parallels, and in the "demi-parallels" or lodgments, 100 to 150 yards long, made on each ap proach about half way between these parallels.
Beyond the third parallel the besieger will probably be met by counter mines, and himself have to resort to mining in order to carry out the crowning of the covered way. The World War developed a more or less new system of siege. See WORLD WAR : ARTILLERY.
Siege in History.-Among great sieges in the world's history may be mentioned those of Troy, Tyre (572, 332 B. C.), Syr acuse (396 B. C.), Saguntum (219 s. C.), Jerusalem (A. D. 70), Acre (1192, etc.), Calais (1347), Orleans (1428), Constan tinople (1453), Haarlem (1572-1573), Leyden (1574), Breda (1625), Rochelle (1628), Magdeburg (1631), Breisach (1638), Taunton (1644-1645), London derry (1689), Gibraltar (1731, 1779, 1782 1783), Prague (1741-1744), Leipsic (1757, 1813), Quebec (1759-1760), Seringapatam (1799), Genoa (1800), Saragossa (1808 1809), Ciudad Rodrigo (1810, 1812), New Orleans (1814), Antwerp (1832), Rome (1849), Sebastopol (1854-1855), Kars (1855), Lucknow (1857), Delhi (1857), Gaeta (1860-1861), Vicksburg (1863), Charleston (1864-1865), Richmond (1864 1865), Metz (1870). Strasburg (1870), Belfort (1870-1871), Paris (1870-1871), Plevna (1877), Khartum (1884), Lady smith (1900), Port Arthur (1904), Adri anople (1912) ; Liege (1914), Przemysl (1914-1915) ; Verdun (1915-1916).