Since the float is in equilibrium on the surface of the vessel, its weight is equal to the weight of the liquid which it displaces. Therefore, if the float were to be replaced by the liquid in which it floats, this liquid would occupy a volume equal to the volume of the submerged part of the float, and the level of the liquid would not change. Consequently the law of communicating vessels will not be broken if there is a float on the surface of the liquid in one of the vessels.