stipulation is void, because the performance of
the act to be promised is a physical impossibility.

6 Conditions relating to past or present time either make the obligation
void at once, or have no suspensive operation whatever. Thus, in the
stipulation 'Do you promise to give so and so, if Titius has been
consul, or if Maevius is alive?' the promise is void, if the condition
is not satisfied; while if it is, it is binding at once: for events
which in themselves are certain do not suspend the binding force of an
obligation, however uncertain we ourselves may be about them.

7 The performance or nonperformance of an act may be the object of a
stipulation no less than the delivery of property, though where this is
the case, it will be best to connect the nonperformance of the act to be
performed, or the performance of the act to be omitted, with a pecuniary
penalty to be paid in default, lest there be doubt as to the value of
the act or omission, which will make it necessary for the plaintiff to
prove to what damages he is entitled. Thus, if it be a performance
which is stipulated for, some such penalty should be added as in the
following: 'If so and so is not done, do you promise to pay ten aurei as
a penalty?' And if the performance of some acts, and the nonperformance
of others, are bargained for in the same stipulation, a clause of the
following kind should be added, 'If any default is made, either as
contrary to what is agreed upon, or by way of nonperformance, do you
promise to pay a penalty of ten aurei?'

TITLE XVI. OF STIPULATIONS IN WHICH THERE ARE TWO CREDITORS OR TWO
DEBTORS

There may be two or more parties on either side in a stipulation, that
is to say, as promisors or promisees. Joint promises are so constituted
by the promisor answering, 'I promise,' after they have all first
asked the question; for instance, if after two promises have separately
stipulated from him, he answers, 'I promise to give so and so to each of
you.' But if he first promises to Titius, and then, on another's putting
the question to him, promises to him too, there will be two distinct
obligations, namely, one between him and each of the promisees, and they
are not considered joint promisees at all. The usual form to constitute
two or more joint promisors is as follows,--'Maevius, do you promise to
give five aurei? Seius, do you promise to give the same five aurei?' and
in answer they reply separately, 'I promise.'

1 In