13. The Water Commission shall, within a period to be fixed by the order of the Governor (who is hereby authorized to extend such period if in his opinion it shall appear necessary to do so), make a register setting forth-
(a) the approximate amount of water which, at the date of the coming into force of this Law, was accustomed to be supplied from the Arab Ahmet or Silikdar aqueduct free of charge to any Mosque or other Moslem religious institution or to any Vakf bath or other Vakf property;
(b) the rights to receive water from the above-named sources which, at the date of coming into force of this Law, were lawfully held and enjoyed by any person and the conditions as to payment of an ijare or annual rent or otherwise subject to which such rights were held.