Agni is the altar-fire. Originally fire, Agni, in distinction from sun and lightning, is the fire of sacrifice; and as such is he great. One reads in v. 3. 1-2, that this Agni is Varuna, Indra; that in him are all the gods. This is, indeed, formally a late view, and can be paralleled only by a few passages of a comparatively recent period. Thus, in the late hymn i. 164. 46: "Indra, Mitra, Varuna, Agni, they say; he is the sun (the bird in the sky); that which is but one they call variously," etc. So x. 114. 5 and the late passage iii. 38. 7, have reference to various forms of Agni. Indra had a twofold nature in producing the union of lightning and Agni; and this made him mysteriously great. But in Agni is found the first triality, which, philosophically, is interpreted as a trinity. The fire of the altar is one with the lightning, and, again, one with the sun. This is Agni's threefold birth; and all the holy character of three is exhausted in application where he is concerned. It is the highest mystery until the very end of the Vedic age. This Agni it is that is the real Agni of the Rig Veda--the new Agni; for there was probably an Agni cult (as simple fire) long before the _soma_ cult. Indra and Agni are one, and both are called the slayers of the demons[1]. They are both united as an indissoluble pair (iii. 12, etc.). Agni, with, perhaps, the exception of Soma, is the most important god in the Rig Veda; and it is no chance that gives him the first place in each family hymn-book; for in him are found, only in more fortunate circumstances, exactly the same conditions as obtain in the case of Indra. He appealed to man as the best friend among divine beings; he was not far off, to be wondered at; if terrible, to be propitiated. He was near and kind to friends. And as he seemed to the vulgar so he appealed to the theosophy which permeates the spirit of the poets; for he is mysterious; a mediator between god and man (in carrying to heaven the offerings); a threefold unity, typical of earth, atmosphere, and heaven. From this point of view, as in the case of Indra, so in the case of Agni, only to a greater extent, it becomes impossible to interpret Agni as one element, one phenomenon. There is, when a distinction is made, an _agni_ which is single, the altar-fire, separate from other fires; but it is seldom that Agni is not felt as the threefold one.