87.—No will or any part thereof, which is in any manner revoked, shall be revived otherwise than by the re-execution thereof or by a codicil duly executed and showing an intention to revive it; and when any will or codicil which is partly revoked, and afterwards wholly revoked, is revived, such revival shall not extend to so much thereof as was revoked before the revocation of the whole thereof, unless an intention to the contrary is shown.