88: "...Agni, who is the source of all that gives light and heat.  So that there are different species of Agni (fire); but "whatever other fires there may be, they are but the ramifications of Agni, the immortal" (Rig Veda, L, 59 I).  The primary division of Agni is threefold.  "Agni," says the Vishnu Parana, "has three sons, Suchi, Pavamana, and Pavaka" (I, x).  Suchi means the Saura, or Solar fire; Pavamana means Nirmathana, fire produced by friction, as the friction of two pieces of wood; and Pavaka means the vaidyuta or fire of the firmament, i.e. the fire of the lightning, or electric fire.
The sources of these three fires I may observe in passing, constitute the three principal deities spoken of in the Veda, namely, Surya, the sun, representing the solar fire; Indra (and sometimes, Vayu) the rain-producing deity, representing the fire of the firmament; and Agni, representing the terrestrial fire, the fire produced by friction (Nirukta, VII, 4); and all these three, be it remembered, are merely the ramifications of one Agni; which in its turn is an emanation from the Supreme One, as the reader will find from the allegorical description given of Agni as being the mouth-born son of Brahma, in the Vishnu purana.
Now, each of the triple forms of Agni has numerous subdivisions.  The solar fire is distinguished by several divisions according to the nature of the rays emitted by the great luminary."—The Theosophist, Vol VII, p. 196.