Revocation must be communicated, or at least brought to the knowledge of the offeree, to have any effect. As we have seen, an acceptance may take effect at the moment it is dispatched. A revocation, on the contrary, is not effective until the moment it is received. A person, therefore, who has accepted an offer not known by him to have been revoked, may safely act on the footing that the offer and acceptance constitute a contract binding on both parties. A person who has received an offer by post or telegraph, and posted or telegraphed his acceptance, has thereby created a binding contract, though notice of revocation of the offer has been mailed or wired to him before his acceptance.96 The law, it is said, regards the proposer as making his offer during every instant of time that his letter is traveling, and during the period that may be considered as a reasonable time for acceptance. The party to whom the offer is made is therefore entitled to consider that it is still being made, unless he has notice to the contrary, and that his acceptance concludes a binding contract. The revocation cannot be held to be communicated merely because it has been put in the course of transmission. If, after an offer has been posted, or sent by any other means, the proposer sends a withdrawal by such means that it reaches the person to whom the offer was sent at the same time as the offer, this is a good revocation, and an acceptance of the offer will be ineffectual.87
There has been some difficulty in cases in which the offeror has done some act indicating an intention to retract, as by a sale of property offered, putting it out of his power to perform, but without communicating his revocation. It is probably settled that any overt act clearly showing an intention to revoke is enough, provided the person to whom the offer was made has notice of such act before he accepts. The revocation need not be communicated, but it is sufficient if he has knowledge of acts clearly indicating an intention to revoke.98 It is not clearly settled what would be sufficient notice. It might probably be said that the notice must be such as reasonably amounts to knowledge of acts inconsistent with the continuance of the offer. In case of an offer to sell specific property, actual knowledge of its sale to another would clearly show an intent to revoke, but it is doubtful whether information from a stranger that such a sale has been made, or that the proposer has changed his mind, would be sufficient, as it would scarcely be reasonable to require a man to believe and act on such statements. In the absence of sufficient notice or knowledge of a revocation, the offer, according to the better doctrine and the weight of authority, continues open and will be turned into a binding promise by its acceptance." Some courts, however, seem to have held, contrary to reason and principle, that notice of withdrawal is not necessary.1 Where the parties are dealing with each other at
62 Kan. 853, 62 Pac. 663; Bradford v. Foster, 87 Tenn. 4, 9 S. W. 195. See "Specific Performance," Dec. Dig. (Key-No.) § 67; Cent. Dig. § 178.
96 Byrne v. Tienhoven, 5 C. P. Div. 349; Henthorn v. Frazer  66 L. T. (N. S.) 439, 2 Ch. 27; Harris' Case, L. R. 7 Ch. App. 587; Tayloe v. Insurance Co., 9 How. 390, 13 L. Ed. 187; Patrick v. Bowman, 149 U. S. 411, 13 Sup. Ct, 811, 866, 37 L. Ed. 790; Hamilton v. Insurance Co., 5 Pa. 342; Lungstrass v. Insurance Co., 48 Mo. 201, 8 Am. Rep. 100; Kempner v. Cohn, 47 Ark. 519, 1 S. W. 869, 58 Am. Rep. 775; Wheat v. Cross, 31 Md. 99, 1 Am. Rep. 28; Hallock v. Insurance Co., 26 N. J. Law, 268; Faulkner v. Hebard, 26 Vt. 452; McCotter v. City of New York, 37 N. Y. 325; Weiden v. Woodruff, 38 Mich. 130; Crocker v. Railroad Co., 24 Conn. 249; Cobb v. Foree, 38 111. App. 255; Brauer v. Shaw, 168 Mass. 198, 46 N. E. 617, 60 Am. St. Rep. 387; Wester v. Casein Co. of America, 140 App. Div. 442, 125 N. Y. Supp. 335. See "Contracts," Dec. Dig. (Key-No.) § 19; Cent. Dig. §§ 57-60.
97 Dunmore v. Alexander, 9 Shaw & D. 190. Suppose, however, the letter containing the offer should be read, and an acceptance dispatched in good faith, before the letter containing the withdrawal is opened. It would seem, on principle, that in such a case the acceptance must be effectual. See "Contracts," Dec. Dig. (Key-No.) §§ 19, 22; Cent. Dig. §§ 57-60, 104-108.
98 Dickinson v. Dodds, 2 Ch. Div. 463; Coleman v. Applegarth, 68 Md. 21, 11 Atl. 284, 6 Am. St Rep. 417. See "Contracts," Dec. Dig. (Key-No.) § 19; Cent. Dig. §§ 57-60.
99 Boston & M. R. R. Co. v. Bartlett, 3 Cush. (Mass.) 224, 225; Great Northern R. Co. v. Witham, L. R. 9 C. P. 16; Eskridge v. Glover, 5 Stew. & P. (Ala.) 264, 26 Am. Dec. 344; Houghwout v. Boisaubin, 18 N. J. Eq. 318; Henthorn v. Frazer [1S92] 66 L. T. (N. S.) 439, 2 Ch. 27; Cheney v. Cook, 7 Wis. 413; School Directors v. Trefethren, 10 111. App. 127; Paddock v. Davenport, 107 N. C. 710, 12 S. E. 464; Wall v. Railroad Co., 86 Wis. 48, 56 N. W. 367. And see Dambmann v. Lorentz, 70 Md. 380, 17 Atl. 389, 14 Am. St Rep. 364. See, also, post, p. 148. See "Contracts," Dec. Dig. (Key-No.) §§ 19, 22; Cent. Dig. §§ 57-60, 101,-108.
1 Tucker v. Woods, 12 Johns. (N. Y.) 190, 7 Am. Dec. 305; Bean v. Bur-bank, 16 Me. 458, 33 Am. Dec. 681; Gillespie v. Edmonston, 11 Humph. (Term.) 553. And see Cooke v. Oxley, 3 Term R. 653. This case has been very much criticised and disapproved in so far as it seems to hold that, where an offer gives a specified time within which it may be accepted, an acceptance within that time, without notice that the offer has been revoked, does not bind; that is to say, that notice of the revocation is not necessary. If the case was intended to go this far, it is not considered as authority In this country. Boston & M. R. R. Co. v. Bartlett, 3 Cush. (Mass.) 224. Nor, it seems, is It followed, even in England, to such an extent as we have suggested. Indeed, a later English case says: "All that Cooke v. Oxley affirms is that a party who gives time to another to accept or reject a proposal is nor. bound to wait till the time expires. * * * The offer may be revoked before acceptance. If the offer Is not retracted, it is in force as a continuing offer till the time of accepting or rejecting it has arrived." Stevenson v. McLean, a distance by correspondence, it is the settled law, in these as in other cases, that the offer continues open until notice of its withdrawal is not only sent, but received by the party to whom it was made, and is turned into a binding promise if accepted before receipt of the notice.2 Knowledge in these cases also may be equivalent to notice sent and received.
The case of an offer made to the public generally by publication stands on a different footing from an offer made directly to a definite person. Such an offer may be revoked in the manner in which it was made.8
24. An offer will lapse, and so be determined without express revocation, so that a subsequent acceptance will have nc effect -
(a) On the efflux of a time specified for acceptance, or of a reasonable time where no time is specified;
(b) On its rejection;
(c) On failure of the acceptance to comply with the terms of the offer, which is equivalent to rejection;
(d) On the death or insanity of either party before acceptance.