It is not yet perhaps fully settled whether an offer is revoked by knowledge on the part of an acceptor that the offeror is no longer willing to enter into such a contract as was proposed by his offer, when that knowledge comes not from the offeror himself or with his cognizance, but through other channels. It was held by the English Court of Appeal that knowledge on the part of an offeree that land which had been offered to him for sale had subsequently been sold to another, prevented him from making an effectual acceptance of the offer.58 This case has been followed in the United States; 59 but has also been severely criticised."60 Certainly there are both theoretical and practical difficulties involved in any rule allowing an effective revocation to be made by any one but the offeror. In theory, as an offer must be made by an act of the offeror moving toward the offeree, and no statement by third persons is sufficient,61 so it would seem that an offer could only be withdrawn by a direct expression of volition on the part of the offeror to the person to whom he had previously made the offer. Though the expression is common especially in the earlier cases of "communication" or "notice" of revocation as if communication or notice were made of a revocation that had previously taken place, this use of language has descended from a time when mutual assent in contracts meant actual mutual assent, not that expressed by one party to the other. At the present day it is more accurate to say that communication is essential to the existence of revocation, indeed is the revocation. If so, it seems that the act of the offeror is as essential to withdraw his offer as to create it, and that the only way he can make his act effective is by communication from himself or his agent.62 From a practical standpoint, also, there is difficulty in deciding when knowledge received in a roundabout way through third persons indicates with sufficient clearness that the offeror is no longer disposed to keep his offer good. Must the offeree give credit at his peril to haphazard information, or what degree of certainty or probability must exist in order to make the words of an outsider effectual to revoke the offer? Nevertheless in view of the uniformity of the few decisions directly in point, and of the manifest lack of equity in an attempt to enforce a contract which the acceptor knew at the time of his acceptance was contrary to the wishes of the offeror, it is likely that the English case on the point will be followed.
56See infra, Sec. 89.
57 See unfra, Sec. 58.
58 Dickinson v. Dodds, 2 Ch. D. 463. Comments on this case in Henthorn v. Fraser  2 Ch. 27, indicate that the English court regards the knowledge of the offeree as the vital circum-stance.
59Coleman v. Applegarth, 68 Md. 21, 11 Atl. 284, 6 Am. St. Rep. 417; Witters p. Lincoln (S. Dak.), 135 N. W. 712; Frank v. Stratford-Hand-cock, 13 Wyo. 37,77 Pac. 134, 67 L. R A. 571, 110 Am. St. Rep. 963. But ep. Sherley v. Peehl 84 Wis. 46, 54 N.W.267. In this case an offer to discount a note was made to the holder and later the maker failed. The holder knowing of the failure accepted the offer, and was allowed to enforce a contract against the offeror. Also Arentsen v. Moreland, 122 Wis. 167, 99 N. W. 790, 65 L. R. A. 973, where knowledge that a vendor had contracted to sell the timber on certain land did not preclude the vendee from taking an option to buy the land, with the timber, accepting the option and, on refusal of the vendor to convey the timber, recovering damages for its value.
60Langdell, Summary of Contracts, Sec.181; Wald's Pollock, Contracts (3d. ed.), 32.
Sec. 58. Revocation of offer contemplating a series of performances. Most offers contemplate a single acceptance by the offeree by an indivisible act or by an indivisible promise or set of promises. It is possible, however, to make a divisible offer requesting a series of acts or promises to be given from time to time, and agreeing in return to give a series of performances each of which is to be set off against a corresponding act or promise of the offeree. If an offer is of this divisible character it may be revoked not only before any acceptance but also as to any portion of the offer still unaccepted even after acceptance of some of the series of transactions proposed by the offer.63 It is often a difficult question of construction whether an offer contemplates a series of contracts, as thus suggested or requests a single immediate promise to perform the whole series of acts. If the latter construction is the true one an acceptance creates an immediate bilateral contract which binds both parties irrevocably to perform all the acts.64
61 See supra, Sec. 23
62 See supra, Sec. 23.