If any person against whom the right shall have so accrued on an award, or on any such contract, shall by writing signed by him or his agent promise payment of money on such award or contract, the person to whom the right shall have so accrued may maintain an action or suit for the moneys so promised within such number of years after such promise as it might originally have been maintained within upon the award or contract, and the plaintiff may either sue on such a promise, or on the original cause of action, and in the latter case, in answer to a plea under the sixth section, may, by way of replication, state such promise, and that such action was brought within such number of years thereafter; but no promise, except by writing as aforesaid, shall take any case out of the operation of the said sixth section, or deprive any party of the benefit thereof. An acknowledgment in writing as aforesaid, from which a promise of payment may be implied, shall be deemed to be such promise within the meaning of this section.