§ 20. According to article 52 the conflicting States which resort to arbitration shall sign a special Act, the _Compromis_, in which is clearly defined: the subject of the dispute; the time allowed for appointing the arbitrators; the form, order, and time in which the communications referred to in article 63 of Convention I. must be made; the amount of the sum which each party must deposit in advance to defray the expenses; the manner of appointing arbitrators (if there be occasion); any special powers which may eventually belong to the Tribunal, where it shall meet, the languages to be used, and any special conditions upon which the parties may agree. Should, however, the conflicting States prefer it, the Permanent Court at the Hague is competent to draw up and settle the _Compromis_, and the Court is likewise in some other cases competent to settle the _Compromis_ (articles 53-54). The parties may agree to have recourse to the Permanent Court of Arbitration which was instituted by the Hague Convention and regarding which details have been given above, Vol. I., §§ 472-476, but they may also assign the arbitration to one or several arbitrators chosen by them either from the members of the Permanent Court of Arbitration or elsewhere (article 55). If they choose a head of a State as arbitrator, the whole of the arbitral procedure is to be determined by him (article 56). If they choose several arbitrators, an umpire is to preside, but in case they have not chosen an umpire, the arbitrators are to elect one of their own number as president (article 57). If the _Compromis_ is settled by a Commission, as contemplated by article 54 of Convention I., and in default of an agreement to the contrary, the Commission itself shall form the Arbitration Tribunal (article 58). In case of death, resignation, or disability of one of the arbitrators from any cause, his place is to be filled in accordance with the method of his appointment (article 59). The place of session of the arbitrators is to be determined by the parties; but if they fail to do it, the place of session is to be the Hague, and the place of session may not be changed by the arbitrators without the consent of the parties; the Tribunal may only sit in the territory of a third State with the latter's consent (article 60). The International Bureau of the Court at the Hague is authorised to put its offices and its staff at the disposal of the contracting Powers in case the parties have preferred to bring their dispute before arbitrators other than the Permanent Court of Arbitration (article 47). [Sidenote: Procedure of and before the Arbitral Tribunal.] § 21. The parties may agree upon such rules of arbitral procedure as they like. If they fail to stipulate special rules of procedure, the following rules are valid, whether the parties have brought their case before the Permanent Court of Arbitration or have chosen other arbitrators (article 51):--