The herald reads a proclamation declaring a night of general festivities to celebrate both the destruction of the Turkish fleet and Othello's recent marriage.
This short scene is occasionally combined with the scene that follows. Chiefly, it functions in approximately the same way that a curtain is pulled in a modern theater to indicate the passing of time. We know that the Turkish fleet has suffered "perdition," largely due to the "noble" and "valiant" efforts of Othello, and that the rejoicing celebrates the military victory and also the general's recent marriage. In short, the Moor has proclaimed a holiday to be held from five o'clock until eleven, during which the soldiers and citizens can dance, make bonfires, or make "revels [however] his [addiction] leads him" (6).
Dramatically, this mood of merrymaking and celebration is a strong contrast to the tragedy that is about to follow and, in addition, the chaos gives Iago sufficient time and opportunity to set his traps for the unsuspecting Othello. Also, this feasting and dancing takes place at night, and earlier Iago proclaimed that "hell and night / Must bring this monstrous birth [of his evil design] to the world's light" (I.3, 409-410). This scene preludes that horror.
mere perdition (3) complete destruction.
addiction (6) an inclination.