§ 489. The next subject which we propose to consider is the assent of the parties to a contract. There are three requisites to legal assent: namely, it should be mutual; it should be without restraint; it should be understandingly made, and without error or mistake. We shall consider, therefore, the qualities which characterize consent, under three heads: namely, 1st. Mutuality of Assent; 2d. Duress; 3d. Mistake.

§ 490. In order to create a contract, it is essential that there should be a reciprocal assent to a certain and definite proposition.1 So long as any essential matters are left open for further consideration, the contract is not complete;2 and the minds of the parties must assent to the same thing in the same sense.3 A mere offer not assented to, constitutes no contract, for there must be not only a proposal, but an acceptance thereof.4 So

1 If one party attaches to a proposition of the other a signification not authorized by reasonable inference or fair understanding, what injury results from the misunderstanding must fall upon him. Thompson v. Ray, 46 Ala. 224 (1871). Saflfold, J.

2 Brown v. New York Central Railroad, 44 N. Y. 79 (1870). See also Lyman v. Robinson, 14 Allen, 254; Ridgway v. Wharton, 6 H. L. C. 268. A paper signed by persons engaged in a particular trade, as follows: "We, the undersigned, hereby agree to pay our share of costs, equally divided, for the purpose of engaging counsel and to bring our cases before the courts," does not create a contract with an attorney to whom a portion of the subscribers, deliver the paper, without the knowledge of the others; at least such a paper cannot be enforced against the other subscribers. Smith v. Duch-ardt, 45 N. Y. 597 (1871).

3 Hartford & N. H. Railroad v. Jackson, 24 Conn. 514.

4 Tucker v. Woods, 12 Johns. 190; Jackson v. Galloway, 5 Bing. N. C. 75, 76; Rowell v. Montville, 4 Greenl. 270; Johnson v. King, 2 Bing. 270; Cope v. Albinson, 8 Exch. 185; 16 Eng. Law & Eq. 470, and Bennett's note; Gaunt v. Hill, 1 Stark. 10; Eskridge v. Glover, 5 Stew. & Port. 264; Governor, etc. v. Petch, 10 Exch. 610; 28 Eng. Law & Eq. 470. Where one party made a written proposition to another to do certain work for him, and the latter purchased some materials for the work, but which might be as long as a proposal is not acceded to, it is binding upon neither party, and may be retracted.1 Thus, where A. applied to an insurance company for insurance, and agreed upon the rates to be paid, and the policies were made out, but not delivered, because A. refused to accept them or sign the notes, it was well used for other purposes, and began the work, but gave no notice to the other of his acceptance of the proposition, it was held to be no binding contract, since a mere mental determination to accept would not be sufficient. White v. Corlies, 46 N. Y. 467 (1871).

1 In an action for services in selling an estate for the defendant, it appeared that the defendant told the plaintiff that he would give him a certain sum if he would obtain a purchaser; that the plaintiff, who was not a broker, neither did nor said any thing at the time to show that he accepted the offer, but within a few days told J. S. that the defendant wanted to sell, and took him to see, but did not find, the defendant; and that afterwards J. S. bought the estate, but the defendant did not know till after the sale that the plaintiff had done any thing to aid it. The Supreme Court of Massachusetts held that there was evidence for the jury of a continuing offer, of an acceptance, and of a performance by the plaintiff of the contract thus formed. Bornstein v. Lans, 104 Mass. 216 (1870). "The case," say the court, "was evidently tried in the Superior Court, upon the assumption that there was no valid contract between the parties, and that there was a mere proposition on the part of the defendant, without any acceptance on the part of the plaintiff, so that their minds never met on the subject-matter. But we think that an offer which is in its nature continuous and open for some period of time, and which is also conditional upon an event which may not immediately happen, but must at all events be attended with some delay, becomes a valid contract on good consideration, if accepted in fact, and upon the fulfilment of the condition, within a reasonable time and before an actual retraction of the offer. In Train v. Gold, 5 Pick. 380, 384, the court (Wilde, J.) say: ' Nor is it necessary that the consideration should exist at the time of making the promise; for if the person to whom the promise is made should incur any loss, expense, or liability in consequence of the promise, and relying upon it, the promise thereupon becomes obligatory. Thus if A. promises B. to pay him a sum of money if he will do a particular act, and B. does the act, the promise thereupon becomes binding, although B., at the time of the promise, does not engage to do the act. In the intermediate time the obligation of the contract or promise is suspended; for until the performance of the condition of the promise there is no consideration, and the promise is nudum pactum; but on the performance of the condition by the promisee, it is clothed with a valid consideration, which relates back to the promise, and it then becomes obligatory.' See also Goward v. Waters, 98 Mass. 596. The converse of the proposition is laid down in Ball v. Newton, 7 Cush. 599, in which case it was held that a written promise to pay certain fees is not binding, and cannot be enforced in favor of a party who rendered the services without any knowledge of or reliance upon such promise." held that he might retract, and that the bargain was not completed.1 And if one party offers to transport merchandise not exceeding a certain quantity, at a certain rate, during certain months in the year, and the other party replies, merely accepting the terms, but does not engage to send any merchandise, there is no completed contract between them.2 Nor does it matter by what mode assent is expressed, provided it be intelligible. Thus, it may be given by a nod, by shaking hands, taking off a shoe, or drawing a shilling across the hand, all of which are signs of ratification among different nations.3 Again, a blow of the hammer at an auction sale is sufficient to complete the contract, unless the offer be retracted before the hammer is down.4 So, also, a contract may be created between deaf and dumb persons, so as to be completely obligatory, by any signs which are reciprocally intelligible; for assent may be as perfectly given by means of pantomime as by the more refined hieroglyph of words. A contract may be made by telegram,5 and the contract is complete when the acceptance or telegram is forwarded.6 But if the message is not properly transmitted, the sender is bound by it only as he sent it, and not as it was erroneously transmitted by the telegraph operator.7 And the extent to which telegrams are to be treated as written contracts depends much upon the circumstances under which they are sent, and the intent and object for which they are transmitted.8