Each House shall elect its own Chairman and Deputy Chairman and shall prescribe their powers, duties, and terms of office. ARTICLE 22. All matters in each House shall, save as otherwise provided by this Constitution, be determined by a majority of the votes of the members present other than the Chairman or presiding member, who shall have and exercise a casting vote in the case of an equality of votes. The number of members necessary to constitute a meeting of either House for the exercise of its powers shall be determined by its Standing Orders. ARTICLE 23. The Parliament/Oireachtas shall make provision for the payment of its members and may in addition provide them with free travelling facilities in any part of Ireland. ARTICLE 24. The Parliament/Oireachtas shall hold at least one session each year. The Parliament/Oireachtas shall be summoned and dissolved by the Representative of the Crown in the name of the King and subject as aforesaid the Chamber/Dail Eireann shall fix the date of re-assembly of the Parliament/Oireachtas and the date of the conclusion of the session of each House provided that the sessions of the Senate/Seanad Eireann shall not be concluded without its own consent. ARTICLE 25. Sittings of each House of the Parliament/Oireachtas shall be public. In cases of special emergency either House may hold a private sitting with the assent of two-thirds of the members present. SECTION II.--LEGISLATIVE PROVISIONS. B.--THE CHAMBER OF DEPUTIES/DAIL EIREANN. ARTICLE 26. The Chamber/Dail Eireann shall be composed of members who represent constituencies determined by law. The number of members shall be fixed from time to time by the Parliament/Oireachtas, but the total number of members of the Chamber/Dail Eireann shall not be fixed at less than one member for each thirty thousand of the population, or at more than one member for each twenty thousand of the population: Provided that the proportion between the number of members to be elected at any time for each constituency and the population of each constituency, as ascertained at the last preceding census, shall, so far as possible, be identical throughout the country. The members shall be elected upon principles of Proportional Representation. The Parliament/Oireachtas shall revise the constituencies at least once in every ten years, with due regard to changes in distribution of the population, but any alterations in the constituencies shall not take effect during the life of the Chamber/Dail Eireann sitting when such revision is made. ARTICLE 27.