Soma, the Avestan Haoma ("the Pressed Juice"), is the deity of the whole of the ninth book of the Ṛgveda and of six hymns elsewhere. The plant, which has not been identified for certain with any modern species, yielded, when its shoots were pressed, a juice which after careful straining was offered, pure or with admixture of milk, etc., to the gods and drunk by the priests. The colour was brown or ruddy, and frequent mention is made of the stones by which it was pounded, though it seems also to have been produced by mortar and pestle, as among the Parsis. As passing through the filter or strainer, soma is called pavamāna ("flowing clear"). Besides milk, sour milk and barley water were commonly added, and hence Soma is lord of the waters, who makes the rain to stream from heaven. The waters are his sisters, and he is the embryo or child of the waters. The sound of the juice as it flows is likened to thunder, its swiftness to that of a steed.
The exhilarating power of the soma doubtless explains his divinity. It is a plant which confers powers beyond the natural, and thus soma is the draught of immortality (amṛta), the ambrosia. The gods love it; it gives them immortality no less than men, and one hymn depicts the ecstasy of feeling produced in Indra by the drink, which makes him feel able to dispose of the earth at his pleasure. Soma is also rich in healing and lord of the plants. When quaffed, he stimulates speech and is the lord of speech. He is a maker of seers, a protector of prayer, and his wisdom is extolled. He gazes with wisdom on men and so has a thousand eyes. The fathers, no less than men and gods, love him, and through him they found the light and the cows. The great deeds of the gods owe their success to their drinking the soma, with three lakes of which Indra fills himself for the slaying of Vṛtra. When drunk by Indra, Soma made the sun to rise in the sky, and hence Soma is declared to perform the feat; he found the light and made the sun to shine. So, too, he supports the two worlds and is lord of the quarters. Like Indra he is a terrible warrior, ever victorious, winning for
