however withdrawn, in law, until a notice of withdrawal reaches B. This is the important point. Thus if A, in Boston, writes to B, in New Orleans, offering him a certain price for one hundred bales of cotton; and the next day alters his mind, and writes to B, withdrawing his offer; if the first letter reaches B before the second reaches him, although after it was written and mailed, B has a right to accept the offer, and by his acceptance bind A. But if B delays his acceptance until the second letter reaches him, the offer is then effectually withdrawn. It is a sufficient acceptance if B writes to A declaring his acceptance, and puts his letter into the post-office. It seems now quite clear, that as soon as the letter leaves the post-office, or is beyond the reach of the writer, the acceptance is complete. That is, on the 5th of May, A in Boston writes B in New Orleans, offering to buy certain goods there at a certain price. On the 8th of May, A writes that he has altered his mind and cannot give so much, and mails the letter. On the 12th of May, B in New Orleans receives the first letter, and the next day, the 13th, answers it, saying that he accepts the offer and mails his letter. On the 14th, he receives the second letter of A withdrawing the offer. Nevertheless the bargain is complete and the goods are sold. But if B had kept his letter of acceptance by him until he had received A's letter of withdrawal, he could not then have put his letter into the mail and bound A by his acceptance.

The late cases would also indicate, that if the letter of withdrawal reaches B after he has put his letter of acceptance into the post-office, but before it has gone, and while he could still take it back if he chose, he may disregard the withdrawal of the offer, and let his letter go on its way. This certainly is not settled; but the dicta of judges, and the principles on which the later decisions rest, would seem to lead to the conclusion that the contract is entirely complete as soon as the letter is in the post-office.

The party making the offer by letter is not bound to use the same means for withdrawing it which he uses for making it; because any withdrawal, however made, terminates the offer, if only it reaches the other party before his acceptance. Thus, if A in the case just supposed, a week after he has sent his

offer by letter, telegraphs a withdrawal to B, and this withdrawal reaches him before he accepts the offer, this withdrawal is effectual. So if he sent his offer by letter to England, in a sailing ship, and a fortnight after sent a revocation in a steamer, if this last arrives before the first arrived and was accepted, it would be an effectual revocation.

SECTION V.

WHAT EVIDENCE MAY BE RECEIVED IN REFERENCE TO A WRITTEN CONTRACT.

IF an agreement upon which a party relies be oral only, it must be proved by evidence, and any evidence tending to show what the contract was is admissible. But if the contract be reduced to writing, it proves itself; and now no evidence whatever is receivable for the purpose of varying the contract or affecting its obligations. The reasons are obvious. The law prefers written to oral evidence, from its greater precision and certainty, and because it is less open to fraud. And where parties have closed a negotiation and reduced the result to writing, it is to be presumed that they have written all they intended to agree to, and therefore what is omitted was finally rejected by them.

But some evidence may always be necessary, and therefore admissible; as, evidence of the identity of the parties to the contract, or of the things which form its subject-matter. Quite often, neither the court nor the jury can know what person, or what thing, or what land, a contract relates to, unless the parties agree in stating this, or extrinsic evidence shows it. And upon the whole, we cannot state the rule on this subject better than, that, while no evidence is receivable to contradict or vary a written contract, all evidence not otherwise inadmissible -may be received to explain its meaning, and show what the contract is in fact.

There are some obvious inferences from this rule. The first is, that, as evidence is admissible only to explain the contract, if the contract needs no explanation, that is, if it be by itself

perfectly explicit and unambiguous, evidence is inadmissible, because it is wholly unnecessary excepting to vary the meaning and force of the contract, and that is not permitted. Another, following from this, is, that if the evidence purports, under the name of explanation, to give to the contract a meaning which its words do not fairly bear, this is not permitted, because such evidence would in fact make a new contract.

A frequent use of oral evidence is to explain, by means of persons experienced in the subject-matter of the contract, the meaning of technical or peculiar words and phrases; and such witnesses are called experts, and are very freely admitted.

It may be remarked, too, that a written receipt for money is not within the general rule as to written contracts, being always open, not only to explanation, but even to contradiction, by extrinsic evidence. But this is true only of a simple receipt. If a written instrument not only recites or acknowledges the receiving of money or goods, but contains also a contract or -grant, such instrument, as to the contract or grant, is no more to be affected by extrinsic evidence than if it contained no receipt; but as to the receipt itself, it may be varied or contradicted in the same manner as if it contained nothing else. Thus, where a receipt was given for money, and it was said. therein that the money was received "for safe-keeping," the court would not permit the party who gave the money to prove by other evidence that he gave it in payment of a debt, or for any other purpose than "safe-keeping." But they would permit either party to show that the amount was more or less than the sum stated. So if a deed recites that it was made in " consideration of ten thousand dollars, the receipt whereof is hereby acknowledged," the grantor may sue for the money, or any part of it, and prove that the amount was not paid; for this affects only the receipt part of the deed. But he cannot say that the grant of the land was void because he never had his money, nor that any agreement the deed contained was void for such a reason; because, if he proved that the money was not paid for the purpose of thus annulling his grant or agreement, he would be offering evidence to affect the other part of the deed; and that he cannot do.

A certain legal inference from a written promise can no

more be rebutted by evidence than if it were written.

Thus, it is not only true that, if A, by his note, promises to pay B a sum of money in sixty days, he cannot when called upon resist the claim by proving that B, when the note was made, agreed to wait ninety days; but if A promise to pay money and no time is set, this is by force of law a promise to pay on demand, and evidence is not receivable to show that a distant period was agreed upon. Still, where a contract is entire, and a part only is reduced to writing, and the law does not supply the residue, evidence may be received to prove that residue; but not if it materially changes or contradicts what is written. As where a memorandum was made when a horse was hired, in the words, "six weeks at two guineas," and signed, the court would not receive evidence as to the time for which he was hired, nor as to the money to be paid; but permitted evidence as to all other terms of the bargain.

The construction or interpretation of a written contract may sometimes be very material to the interests or rights of third. parties, who had nothing to do with writing it, and were in no way privy to it. In such case, these parties may show by evidence what the contract which purports to have been written really was, as between the parties to it, as freely as if it had not been written.

Generally speaking, all written instruments are construed and interpreted by the law according to the simple, customary, and natural meaning of the words used.

It should be added, that when a contract is so obscure or uncertain that it must be set wholly aside, and regarded as no contract whatever, it can have no force or effect upon the rights or relations of the parties, but they are remitted to their original rights and obligations.

SECTION VI.

OF CUSTOM, OR USAGE.

A CUSTOM, or usage, which may be regarded as appropriate to a contract, has often great weight in reference to it. This it

may have, first, as to the construction or meaning of its words; and next, as to the intention or understanding of the parties.

The ground and reason for this influence of a custom is this. If it exist so widely and uniformly among merchants, and for so long a time, that every merchant must be considered as knowing it, and acting with reference to it, then it ought to have the same force as if both parties expressly adopted it; because each party has a right to think that the other acted upon it.

Sometimes this is carried very far. In one English case, a man had agreed to leave in a certain rabbit warren ten thousand rabbits; and the other party was permitted to prove that, by the usage of that trade, a thousand meant one hundred dozen, or twelve hundred. In an American case, a man agreed to pay a carpenter twelve shillings a day for every man employed by him about a certain building; the carpenter was permitted to prove that, by the usage of that trade, "a day' meant ten hours' work; and as his men had worked twelve and a half, he was permitted to charge fifteen shillings, or for one and one fourth days' work, for every day so spent.

In these cases the custom affected the meaning of the words. But it also has the effect of words; as if a merchant employed a broker to sell his ship, and nothing was said about terms, and the broker did something about it, and the ship was sold, if the broker could prove a universal and well-established custom of that place, that for doing what he did under the employment he was entitled to full commissions, he would have them, as if they were expressly promised.

Any custom will be regarded by the court, which comes within the reason of the rule that makes a custom a part of the contract. It comes within the reason only when it is so far established, and so well known to the parties, that it must be supposed that their contract was made with reference to it. For this purpose, the custom must be established and not casual, uniform and not varying, general and not personal, and known to all the parties. But the degree in which these characteristics must belong to the custom will depend in each case upon its peculiar circumstances. Let us suppose a contract for the making of an article which has not been made until