Revocation of will or codicil

No will or coclicil, nor any part thereof, shall be revoked otherwise than by another will or codicil, or by some writing clccluring an lltentioil to revoke the same and excouted in the manner in which a will is hercilibcfbre required to be cxccuted, or by the burning, tearing or otherwise destroying the same by the tcstator, or by somc person in his presence and by his direction, with the intention of revoking the same.