[Footnote 301: Thus in 1870, during the Franco-German War, the German besiegers of Strassburg as well as of Belfort allowed the women, the children, and the sick to leave the besieged fortresses.] [Footnote 302: See _Land Warfare_, § 129.] That diplomatic envoys of neutral Powers may not be prevented from leaving a besieged town is a consequence of their exterritoriality. However, if they voluntarily remain, may they claim uncontrolled[303] communication with their home State by correspondence and couriers? When Mr. Washburne, the American diplomatic envoy at Paris during the siege of that city in 1870 by the Germans, claimed the right of sending a messenger with despatches to London in a sealed bag through the German lines, Bismarck declared that he was ready to allow foreign diplomatists in Paris to send a courier to their home States once a week, but only under the condition that their despatches were open and did not contain any remarks concerning the war. Although the United States and other Powers protested, Bismarck did not alter his decision. The whole question must be treated as open.[304] [Footnote 303: The matter is discussed by Rolin-Jaequemyns in _R.I._ III. (1871), pp. 371-377.] [Footnote 304: See above, vol. I. § 399, and Wharton, I. § 97.] [Sidenote: Bombardment, how carried out.] § 158. Regarding bombardment, article 26 of the Hague Regulations enacts that the commander of the attacking forces shall do all he can to notify his intention to resort to bombardment. But it must be emphasised that a strict duty of notification for all cases of bombardment is not thereby imposed, since it is only enacted that a commander _shall do all he can_ to send notification. He cannot do it when the circumstances of the case prevent him, or when the necessities of war demand an immediate bombardment. Be that as it may, the purpose of notification is to enable private individuals within the locality to be bombarded to seek shelter for their persons and for their valuable personal property. Article 27 of the Hague Regulations enacts the hitherto customary rule that all necessary steps must be taken to spare as far as possible all buildings devoted to religion, art, science, and charity; further, historic monuments, hospitals, and all other places where the sick and wounded are collected, provided these buildings, places, and monuments are not used at the same time for military purposes. To enable the attacking forces to spare these buildings and places, the latter must be indicated by some particular signs, which must be previously notified to the attacking forces and must be visible from the far distance from which the besieging artillery carries out the bombardment.[305]