Duplicity must be specially pointed out by the demurrer, or it will not hold. But here is no duplicity. It is not double nor inconsistent, to ask for the interest upon the judgment, or to enforce the reasonableness of having it by any agreement of the party or acts of assembly, or other reasonable cause. As the claim of interest was grounded upon the agreement of the defendant, indorsed upon the execution in manner aforesaid, and upon an act of assembly, which is a matter of record, the court had no difficulty in giving judgment for the interest with the principal.