a jury may consider reasonable or otherwise for the other party
to consider it, except by the agreement or concession of the party
making it. Until it is accepted it may be withdrawn, though that be at
the next instant after it is made, and a subsequent acceptance will be
of no avail."

If no time is given, or no consideration for the time given, an offer
therefore may be withdrawn as soon as made if not accepted. A person
may suddenly think of something which leads him to withdraw his offer
as soon as it is out of his mouth, and in doing so is within his
rights, but if he does not, how long does his offer last? A reasonable
time. What this is depends on many things, one of the questions like
so many others in the law to which no definite answer can be given. An
offer to sell some real estate was accepted five days afterward, this
was held to be within a reasonable time. One can readily imagine cases
in which five days would not be thus regarded, or even five hours.

When does assent occur in contracts made by correspondence? The rule
is in nearly every state (Massachusetts being the chief exception)
where an offeree has received an offer by letter and has put his
acceptance in the postoffice, the minds of the parties have met and
made a contract. The post-office is the agency of the offerer both to
carry his offer and bring back the return. If the offeree should use a
different agency, the telegraph for instance, to convey his
acceptance, it would not be binding until the offerer had received and
accepted it. Of course, an offerer by letter may withdraw his offer at
any time. Suppose he should receive an acceptance by letter or
telegraph but deny it, and insist that no contract had been made. Then
the controversy would turn on the proof. If the acceptance had been by
letter, and the offeree could prove that the offeree had written and
mailed it, the offeree's proof would be complete. If the offeree sent
a telegram, then he would be obliged to prove the delivery of the
dispatch. Suppose one should mail a letter of acceptance, but before
its receipt by the offerer, should send a telegram declining the offer
which was received before the letter of acceptance? The acceptance
would stand, for as there had been a meeting of minds when the letter
was put into the postoffice, the offeree could not afterwards withdraw
his offer. A person who makes an offer cannot turn it into an
acceptance. An old uncle wrote to his nephew tha