-The questions presented by the record involve the construction of the contract on which the suit is founded. The contract is not absolute: it is subject to a condition, or a contingency, clearly expressed — the abolition of the mail-route — on the happening of which, the promissor would be discharged from all liability. And it is subject to another condition, on the happening of which there would be an abatement of the sum of money the promissor was bound to pay. The condition is a diminution by the United States of the compensation promised for the carrying of the mail on this route. The parties have thus expressed in writing the conditions by which they are to be bound; and it is not in the power of the courts to imply the existence of others. The rule is of very general, if not universal application, that where parties have entered into written engagements, with express stipulations, these cannot be extended by implication. The presumption is, that, having expressed some, they have expressed all the conditions by which they intend to be bound.
The sum which Dowling promised to pay was not subject *307to abatement, because he may not have received the compensation to which he was entitled under the contract for carrying the mail. It was subject to abatement only in the event the United States diminished the compensation. There was at one time a diminution, but afterwards this order was revoked, and the original compensation restored. The United States paid over the compensation to Tyson, the contractor, to whom alone it could have been properly paid, and with whom alone the contract was made. Such payment the parties must have contemplated. Whatever relation may have existed between Tyson and Blackman, before the sale by the latter of his interest in the mail contract to Dowling, was dissolved by the sale. Blackman, after the sale, had no right or interest which Tyson could represent. He was not entitled to receive, either from Tyson, or from the United States, any part of the compensation due from the latter for carrying the mail. All his rights in this respect passed to Dowling by the sale; and having no rights Tyson could represent, it follows that he is not bound or affected by Tyson’s acts or omissions, or by his want of fidelity to Dowling. To make him answerabie for Tyson’s unfaithfulness is to imply a stipulation not found in the contract.
The rulings of the Circuit Court were inconsistent with these views; and the judgment must be reversed, and the cause iemanded.