Civil Code (Cap. 16), article 479

479. (1) An easement is extinguished when the things subject thereto are in such a condition that it can no longer be exerci sed. (2) Nevertheless, the easement w i l l r e v i v e i f t h e t h i n g s a r e restored in such a manner that i t can be again exercised, unles s a period of time sufficient to raise a presumption of the extinguishment of the easement under article 481 shall have elapsed. by merger or unity of possession,