The burning of images and witches, or of other objects, being so frequently resorted to as a means of destroying baneful influences, the god of fire occupies a rank hardly secondary to Ea. Here, too, the mystical element involved in the use of fire adds to the effectiveness of the method. Water and fire are the two great sources of symbolical purification that we meet with in both primitive and advanced rituals of the past.[366] The fire-god appears in the texts under the double form of Gibil and Nusku. The former occurs with greater frequency than the latter, but the two are used so interchangeably as to be in every respect identical. The amalgamation of the two may indeed be due to the growth of the incantation rituals of Babylon. In some districts Gibil was worshipped as the special god of fire, in others Nusku, much as we found the sun-god worshipped under the names of _Shamas_ and _Utu_, and similarly in the case of other deities. On the supposition that the incantation rituals are the result of a complicated literary process, involving the collection of all known formulas, and the bringing of them into some kind of connection with one another, this existence of a twofold fire-god finds a ready explanation. At Babylon we know Nusku was worshipped as the fire-god. Gibil belongs therefore to another section, perhaps to one farther south. He is in all probability the older god of the two, and the preponderating occurrence of his name in the texts may be taken as a proof of the ancient origin of those parts in which it occurs. There being no special motive why he should be supplanted by Nusku, his preeminence was not interfered with through the remodeling to which the texts were subjected. While bearing in mind that Gibil and Nusku are two distinct deities, we may, for the sake of convenience, treat them together under the double designation of Gibil-Nusku.