Pothier, in his treatise on Sales, states an intermediate doctrine between to be binding until the other party has received information of it.

§ 499. But where a proposal is made by letter, and the other party writes a letter accepting it, and places it in the hands of some person as his agent to forward; the letter, the contract will not be concluded so long as the letter remains in the agent's hands. And although the agent so employed be postmaster, the contract is incomplete until the letter is actually mailed. Where, therefore, A., at Hopkinton, on the 15th of January, made an application to an insurance company at Concord for insurance on his house, and the insurance company stated by letter the terms on which they would insure, and prepared a written application and a premium note, both bearing date of the 16th, to be signed by A., and upon their being returned to the insurance company by mail, a policy bearing the same date was to be forwarded, and A.'s agent, who was the postmaster at Hopkinton, presented the written application and note on the 28th, and A. immediately signed them, and left them in the hands of the postmaster to be forwarded to the insurance company, and the papers were mailed and forwarded on the 3d of February, but the insurance company refused to give A. the policy, - the buildings having been destroyed by fire on the 31st of January,- it was held, in an action for the loss, that no contract of insurance had been completed, the papers signed by A. being in the hands of his agent, and therefore revocable, until after the buildings had been destroyed.1

§ 500. Similar is the case where an order is sent by letter for merchandise. If the article be forwarded before the letter of retraction is received, the contract is completed, and the orderer is in the same predicament as if no retraction had been made. If, however, the order be received, and accepted either by letter, or by a procurement of the articles ordered, or by an action thereupon by the correspondent importing an acceptance, and before the articles were all procured, or were sent, the orderer should retract his order, he would be bound to take the goods already purchased, and to indemnify the other party for his expenses, trouble, and services. Again, if, in such a case, the person of whom they were ordered should order them of a third person, the first orderer would be bound to indemnify the second for all responsibilities incident to the compliance with the order.1

See also M'Intyre v. Parks, 3 Met. 207, where A., being in a State where the sale of lottery tickets was unlawful, wrote to B. in a State where the sale was lawful, to purchase tickets; and it was held that the sale was completed in the State where the assent was given, and not where it was received. See also Plead v. Diggon, 3 Man. & Ryl. 97, and 1 Duer on Ins. 116 to 131, in note, where the subject is fully discussed.

1 Thayer v. Middlesex Mutual Fire Ins. Co., 10 Pick. 326.

§ 501. Where an offer is made and accepted by letters, they form a valid and binding contract, although they have reference to the future making of a formal agreement, and although the parties intend to have a written contract executed.2 But if, after various letters have passed between the parties, and various propositions have been made, the parties finally reduce their agreement to writing, the written contract is to be taken as containing the joint terms of the bargain, and it is not to be varied by the letters or representations made previously;3 for the very object of a written agreement is to obviate all doubt in regard to the exact terms of the bargain, and to satisfy each party of the understanding of the other as to the stipulations of both.4 Yet, if one party be guilty of fraudulent representations to induce the bargain, the other may, upon proof thereof, recover against him.5

§ 502. But if a proposition be made with certain conditions or limitations, the acceptance must correspond to it in terms, or otherwise it will be considered as a new proposition, requiring the subsequent assent of the other party to render it binding.6 A letter accepting an offer of property advertised for sale, but adding some conditions or terms not contained in the original advertisement, does not constitute a complete contract.1 For wherever an agreement is to be established by a series of letters, it can only be created by a proposal being accepted in the terms proposed, without any fresh terms being superadded.2 Thus, where B. was the lessee of a house belonging to C, and D. by letter proposed to B. to purchase the lease for a certain sum, to which proposal B. answered that he would underlet the premises on the terms proposed, it was held that no contract arose, inasmuch as the proposal being for an assignment of the original lease, an agreement to underlet was not an acceptance of the exact terms offered.3 So, where A. offered to purchase the lease of a house from B., if possession should be given on a particular day, and a definitive answer be made within six weeks, and B. accepted, the proposal within the time, but offered possession upon a different day, and A. retracted his offer before the six weeks had elapsed; it was held, that inasmuch as neither party had ever agreed as to the terms proposed by the other, either of them might rescind it at any time.4 So, if a trader order goods of a specified quantity or quality, or upon certain terms of credit, and the goods forwarded be neither of the same quality nor quantity, or if the credit be shorter, he is not bound to receive them.5 . So, where R. in New York wrote to W. in Boston, offering to sell coal, and that he could load 375 tons "on Monday," and on the next Monday after the receipt of the letter W. telegraphed to R., "ship that cargo 375 tons immediately," but R. did not begin to load until nine days afterwards, and then sent 392 tons, it was held that the contract was not complete.1 Yet if goods, different from those ordered be accepted without objection, it will be regarded as an assent to the modification of the original proposal, and the contract will thus be rendered complete.2 So, if particular goods are ordered, and different goods are sent, or differing in quantity from those ordered, there is ordinarily no sale, unless the goods sent be accepted.3