The contract upon which the plaintiff relies was not an unconditional promise to repay to Horace B. Stone the money which he had advanced, nor was it a promise to indemnify Itim, or make a new adjustment with him, upon the happening ot any such event as his resignation of his trust, or his failure to *100have allowance made in his account for the money which he paid in anticipation of the final settlement of his account. It was merely a promise that, if the sum of money which he so paid to Samuel N. and Addison Bancroft should be found to be greater than their just distributive shares as heirs, they would refund the excess with interest, and would indemnify him for and against all loss, cost, damage or expense in consequence of the payment so made. As that contingency has not occurred, and the payment did not exceed their distributive share, nothing ever became due upon the contract. His resignation of his trust has created a state of things which that contract does not provide for and cannot be made to reach, upon any rule of construction.