The latter are closed at the mouth by great round stones in form of a mill-stone, pierced in the centre. This second opening is itself closed by another stone, which is taken away when the water is drawn. This system of closed wells and cisterns by means of a stone is of extreme antiquity.
The latter are sealed at the mouth using large round stones in a mill-stone-like form, pierced in the center. The secondary openings are also closed by additional stones that can be removed for water access. This technique of sealing wells and cisterns with stones is extremely old.