Vattel, III. §§ 168-170--Hall, § 186--Lawrence, § 204--Westlake, II. pp. 76-79--Moore, VII. § 1112--Halleck, II. pp. 59, 67, 185--Taylor, §§ 483-485--Bluntschli, §§ 552-554B--Heffter, § 125--Lueder in Holtzendorff, IV. pp. 448-457--G. F. Martens, II. § 286--Ullmann, § 181--Bonfils, Nos. 1079-1087--Despagnet, Nos. 528-535--Pradier-Fodéré, VI. Nos. 2779-2786--Rivier, II. pp. 284-288--Nys, III. pp. 210-219--Calvo, IV. §§ 2067-2095--Fiore, III. Nos. 1322-1330, and Code, Nos. 1519-1524--Longuet, §§ 58-59--Mérignhac, pp. 171-182--Pillet, pp. 101-112--Zorn, pp. 161-174--Holland, _War_, Nos. 80-83--Rolin-Jaequemyns in _R.I._ II. (1870), pp. 659 and 674, III. (1871), pp. 297-307--Bordwell, pp. 286-288--Meurer, §§ 32-34--Spaight, pp. 157-201--_Kriegsbrauch_, pp. 18-22--_Land Warfare_, §§ 117-138. [Sidenote: Assault, Siege, and Bombardment, when lawful.] § 155. Assault is the rush of an armed force upon enemy forces in the battlefield, or upon intrenchments, fortifications, habitations, villages, or towns, such rushing force committing every violence against opposing persons and destroying all impediments. Siege is the surrounding and investing of an enemy locality by an armed force, cutting off those inside from all communication for the purpose of starving them into surrender or for the purpose of attacking the invested locality and taking it by assault. Bombardment is the throwing by artillery of shot and shell upon persons and things. Siege can be accompanied by bombardment and assault, but this is not necessary, since a siege can be carried out by mere investment and starvation caused thereby. Assault, siege, and bombardment are severally and jointly perfectly legitimate means of warfare.[295] Neither bombardment nor assault, if they take place on the battlefield, needs special discussion, as they are allowed under the same circumstances and conditions as force in general is allowed. The only question here is under what circumstances assault and bombardment are allowed outside the battlefield. The answer is indirectly given by article 25 of the Hague Regulations, where it is categorically enacted that "the attack or bombardment, by any means[296] whatever, of towns, villages, habitations, or buildings, which are not defended, is prohibited." Siege is not specially mentioned, because no belligerent would dream of besieging an undefended locality, and because siege of an undefended town would involve unjustifiable violence against enemy persons and would, therefore, be unlawful. Be this as it may, the fact that defended localities only may now be bombarded, involves a decided advance in the view taken by International Law. For it was formerly asserted by many writers[297] and military experts that, for certain reasons and purposes, undefended localities also might in exceptional cases be bombarded. But it must be specially observed that it matters not whether