The Vedas are four collections of ritual hymns, used in connection with the oblation of the intoxicating juice of the Soma, the moon-plant, or with the sacrificial Fire. The Rig-veda (the oldest) and its supplement the Sāma-veda are now held to have been composed when the Aryans had reached the junction of the Panjāb rivers with the Indus: the Black and White Yajur-veda when they reached the Sutlej and the Jumna; the Atharva-veda, which contains the lower beliefs of aboriginal races, when they had reached Benares. There are gods and goddesses of the sky, the most important being the Sun, and Varuna (the Greek οὐρανός), afterwards a kind of Hindu Neptune, but in these early days represented as sitting in the vault of heaven, and having the sun and stars as the eyes with which he watches the doings of men. His function was to encourage personal holiness as a human ideal. In the mid-air Indra became pre-eminent on Indian soil, where the dependence of an agricultural people on periodical rains made the rain-god an important deity. On earth the most important deities are Soma and Agni (fire) already mentioned. There was also Yama, the beautiful and stately god of death, who though naturally immortal chose to die, and lead the way for mortal successors to the abodes of the dead. Besides the departmental gods, there is in the Vedas a distinct foreshadowing of Pantheism. (3) _The Brāhmanas._ When the Aryans reached the "Midland," the upper Gangetic valley, the Vedic hymns were supplemented by new Scriptures, called Brāhmanas, which were digests of dicta on matters of ritual for the guidance of priests. These were the beginning of Brāhmanism. The elementary Pantheistic theory of the Vedas was developed into a belief in one Spiritual Being or Ātman. When manifested and impersonal, this Being was the neuter Brahma; when regarded as the Creator, he was the masculine Brahmā; but when manifested in the highest order of intellectual men, he was Brāhman, the Brāhman priestly class. Following the Brāhmanas, was a third order of religious literature, the Upanishads. Dr Hopkins has thus summarised the teaching of these three Scriptures. "In the Vedic hymns, man fears the gods. In the Brāhmanas man subdues the gods, and fears God. In the Upanishads man ignores the gods and becomes God." Not that these three kinds of Scripture, these three evolutions of religious speculation, followed one another in chronological order. But this was, roughly, the logical evolution. Finally the doctrine was established that knowledge leads to the supreme bliss of absorption into Brahmā, and with this was combined the theory of transmigration.