It is an elementary principle that the assent of both parties is essential to a valid contract. The minds of the contracting parties must meet, and they must concur as to the terms thereof, or it is no contract. As the principle is sometimes expressed, “ there must be a request by one party, and an assent by the other;” and Parsons says: “ It becomes a contract only when the proposition is met by an acceptance which corresponds with it entirely and adequately.” 1 Parsons on Con., 476.
Again, a promise, to be binding upon the promissor, must be made upon a sufficient consideration. The consideration for the defendant’s promise to excavate for the' cisterns, is alleged in the complaint to have been the promise of the plaintiffs to employ him to do that work and to pay him therefor the agreed price, provided the city should award the cistern contract to the plaintiffs. A promise may be a good consideration for another *372promise ; and it would seem that tbe complaint states a good consideration for the alleged promise of tbe defendant to do tbe work.
It follows from the above rules of law, that, although the defendant offered to do the work at a stipulated price, it is no contract, and he is not bound by such offer, unless the plaintiffs on their part acccepted the offer, and agreed that the defendant should have the job at that price, if the city should accept their proposal.
The learned circuit judge instructed the jury, inter alia, as follows: “ If you find for the plaintiffs that there was an agreement on the part of the defendant to do the excavating, they are entitled to recover the difference between the contract price, twenty cents per cubic yard, and what it appears from the evidence it was worth to do the work,” etc.
This instruction (which appears to be in harmony with the whole charge) rested the plaintiffs’ right to recover upon the single condition that the defendant, on his part, agreed to do the work, and practically excluded from the consideration of the jury the questions, whether the plaintiffs assented to t.he offer of the defendant, and whether they agreed that he should have the job at the stipulated price in case the city should accept their proposal. This was error.
Certain instructions proposed by the defendant’s counsel, and refused, seem to be in accordance with the principles above stated. These are as follows : “ If the jury find from the evidence that the defendant simply said to the plaintiffs, ‘If you get the contract, I will do the work of excavating at twenty cents per cubic yard,’ then the contract is void.” “ Every exec-utory contract must be mutual; that is. both parties must be bound by it. When an executory contract depends for its validity upon the promise of the respective parties, the promises must be mutual in order to bind either party.” These proposed instructions may be liable to some criticism, especially ••the latter, which, in form, asserts an abstract proposition of law; *373yet no good reason is perceived wby these or equivalent instructions should not have been given. ■ r
Other questions are discussed in the arguments of- counsel; but we do not find it necessary to determine them.
By the Court. — The judgment of the circuit court is reversed, and the cause remanded for another trial.