LETTERS OF CREDIT 31 sort. They raise no difficulties on the offer theory, as the terms of the offer provide how the offeree shall be ascertained. They raise no difficulties on the theory of the letter as an acknowledgment of money held to the use of the addressee, for the letter expressly empowers the person to whose use the money is held on condition, to designate the others to whose use it may be held on like condi- tions, and it is a representation that the money is held to such uses on which any one so designated may reasonably rely and may thus raise an estoppel in his favor. So much for so-called questions of assignability. Suppose that the buyer-holder becomes insolvent and the security of the issuer fails after the seller-addressee has done a substantial part of the work of manufacture, but before he has made deliveries- and drawn on the issuer, and the issuer in this interval seeks to cancel. On the offer theory this brings up the much mooted question of an offer requiring by its terms a series of acts to constitute acceptance, which offer is revoked after part of the series of acts has been per- formed, to the prejudice of the offeree, but before acceptance is complete. ^^ Courts have usually been able to avoid this question by straining construction of the transaction so as to make it a bilateral contract, treating the partially completed acceptance as part performance of a bilateral contract. But if the offer theory of letters of credit is adhered to, this way of escape is not open in the present case since by our hypothesis the letter is but an offer and the action of the addressee admits of no other possible con- struction than that of acts falling short of acceptance. Moreover, they are acts in performance of the contract with the buyer-holder and not acts directly in acceptance of the issuer's offer. Protection of the seller-addressee in such a case clearly requires a theory of the letter as acknowledging that money has been received and is held to his use or else a theory of the letter as a substantive transaction of the law merchant. A situation similar on principle where the letter is conditioned on instalments of delivery has already been discussed. Let us carry back the foregoing situation one step further. Sup- pose the buyer-holder, perhaps to make a more advantageous contract elsewhere, seeks to pull out from the sales contract before ^' McGovney, "Irrevocable Offers," 27 Harv. L. Rev. 644.
