18. Where the offer contemplates the performance of or forbearance from an act as the consideration of the promise of the offeror, the performance or forbearance is an acceptance, unless the offeror expressly or impliedly prescribes that the acceptance must be communicated.

19. Where .the offer contemplates a promise as the consideration of the promise of the offeror, communication of the acceptance is essential, unless the offer contemplates that the performance of some overt act manifesting an intention to accept shall be an acceptance, in which case performance of the act is an acceptance.

20. Where the offer contemplates the dispatch of an acceptance by means beyond the acceptor's control, as by post, telegraph, or the offeror's messenger, an acceptance so dispatched is effective from the time of dispatch, unless the offeror makes the formation of the contract dependent upon actual communication to himself.

It is frequently said that it is essential to the formation of a contract that the acceptance be communicated, but, as already intimated, such is far from being the fact. It is, indeed, true that acceptance must be more than mere mental assent.36 Where,

36 WHITE v. CORLIES, 46 N. Y. 467, Throckmorton Cas. Contracts, 1; Felthouse v. Bindley, 11 C. B. (N. S.) 869; Hebb's Case, L. R. 4 Eq. 9; Brogden v. Railway Co., L. R. 2 App. Cas. 691; Stitt v. Huidekoper, 17 Wall. 385, 21 L. Ed. 644; Mactier's Adm'rs v. Frith, 6 Wend. (N. Y.) 103, 21 Am. Dec. 262; Van Valkenburg v. Rogers, 18 Mich. 180; Strasburg R. Co. v. Echternacht, 21 Pa. 220, 60 Am. Dec. 49; Ueberroth v. Riegel, 71 Pa. 280; Beckwith v. Cheever, 21 N. H. 41; Trounstine v. Sellers, 35 Kan. 447, 11 Pac. 441; Gilman v. Kibler, 5 Humph. (Tenn.) 19; Stuart v. Railroad Co., 32 Grat. (Va.) 146; Johnson v. Jacobs, 42 Minn. 168, 44 N. W. 6; Cozart v. Herndon, 114 N. C. 252, 19 S. E. 158.

In Lancaster v. Elliott, 28 Mo. App. 86, it was held that a proposal by defendant to relinquish certain rights against plaintiff was not accepted by writing on the proposal the word "Accepted," and depositing in bank a sum of money to be applied as required by the proposal, where both the proposal and the deposit remained under plaintiff's control.

Where an order for goods is given to an agent of the manufacturer, a letter from the latter to the agent, without any notice to the person who gave the order, is not an acceptance, so as to render the order binding. Harvey v. Duffey, 99 Cal. 401, 33 Pac. 897. And so an application for an insurance policy, given to an agent of the company and by him forwarded to the company, and the Issuance and transmission of the policy to the agent, does not establish a contract of insurance without communication of acceptance for instance, a person by letter offered to buy another's horse for a certain price, adding, "If I hear no more about him, I consider the horse is mine at" that price, and no answer was returned, it was held that there was no contract, and this, though it appeared that the person to whom the offer was sent had made up his mind to accept, and had stated to a third person that the horse was sold.37 A person making an offer may indicate some overt act the performance of which shall be a sufficient manifestation of acceptance, but the statement to a third person that the horse was sold was not such an act, and the silent assent of the offeree was not an acceptance.