What constitutes determinable future time in negotiable instruments

Sec. 4. Determinable future time; what constitutes. - An instrument is payable at a determinable future time, within the meaning of this Act, which is expressed to be payable: (a) At a fixed period after date or sight; or (b) On or before a fixed or determinable future time specified therein; or (c) On or at a fixed period after the occurrence of a specified event which is certain to happen, though the time of happening be uncertain. An instrument payable upon a contingency is not negotiable, and the happening of the event does not cure the defect.