One of the most striking characteristics of the laws governing bills and notes is the necessity for certainty in the terms of the contracts. First of all there must be certainty of payment. The order or promise must be for the payment of a definite sum of money, absolutely and under all circumstances.

5 American and Eng. Ency. of Law, Vol IV, p. 77. This is the definition of Chancellor Kent slightly modified. Other definitions are as follows: - "An open promise in writing by one person to pay another Eerson therein named, or to is order or to bearer, a specified sum of money absolutely and at all events." Daniels on Negotiable Instruments, Sec. 28: "An unconditional promise in writing made by one person to another signed by the maker, engaging to pay on demand, or at a fixed or determinable future time, a certain sum in money to or to the order of a specified person or to bearer." Eng. Bills of Exchange Act, Sec. 83.

• "Bills and notes are governed by the same rules with respect to the certainty required in their terms and their general elements, but, at its inception, a note differs from a bill in the parties thereto. Only the rights of the maker and the payee are involved in a promissory note; when, however, the payee transfers the note to an indorsee the similarity of the note to an accepted bill is perfected; it is then an order from the payee upon the maker for the payment of money to the indorsee; the indorser (payee) is the drawer, the maker of the note is the acceptor, and the indorsee is the payee. Remembering this analogy, decisions with regard to bills may be applied mutatis mutandis to notes." Am. & Eng. Ency. of Law, Vol. IV, p. 79.

Certainty as to time of payment is essential to a bill or note, and any contingency in this respect will render the instrument containing it non-negotiable.7 Exceptions to this last rule exist in conditions sanctioned by commercial usage as to demand, presentment, or sight,8 and contingencies when the payment depends on an event which is bound to ultimately happen.9

The amount of the payment to be made must be certain at the time the order or promise is given. It is sufficient if the amount to be paid at any given time can be ascertained from the face of the note;10 but it is not sufficient that the amount payable is capable of being rendered certain at some future time.11