The second Vedic book, the _Samaveda_, does not contain much fresh material: it is mainly a compilation of the Rigvedic hymns which the priests chanted at the Soma sacrifice. Its sole interest, from a historical point of view, is the evidence it affords of the steady growth of ritualistic tendencies. A new era of Aryan civilization is revealed, however, by the third Veda, the _Yajurveda_. In this book the tribes are found to have extended their area of control down the Ganges valley, and southward along the banks of the Indus. It is of interest to note here that the word “Samudra”, first applied to the broadening Indus where it receives its tributaries, and signifying “collected waters”, became in the _Brahmanas_ the name of the world-encircling ocean, across which in due time loomed the ships which “once in three years” carried to Solomon's order “gold, and silver, ivory (or elephants' tusks), and apes, and peacocks”.[131] [131] 1 _Kings_, x, 22. In the _Yajurveda_ we find that Aryan civilization has developed greatly in the course of three or four centuries. Powerful tribes have established kingdoms, and small states are being subjected to the larger. The hardened system of social organization is reflected by the references to the four distinct castes. Hitherto the Kshatriyas have controlled the destinies of the people, but now the Brahmans achieve an intellectual conquest and impose their sway over kings and nobles. The holy men are no longer the humble servants of generous patrons; they are the human representatives of the all-controlling deities. “Verily, there are two kinds of gods; for the gods themselves, assuredly, are gods, and those priests who have studied and teach Vedic lore, are the human gods.” The offerings to the deities are “consecrated by the feeding of priests”.[132] [132] _Satapatha Brahmana_, translated by Professor Eggeling, Part I, p. 374 (_Sacred Books of the East_). Even the gods become dependent upon the priests, who provided them by offering sacrifices with the “food” they required, and also with the Soma which gave them length of years. Indra could not combat against the Asuras without the assistance of the priests who chanted formulas to ensure victory; it was, therefore, due to the power exercised, in the first place, by the priests that the drought demon was overcome and rain fell in abundance. [Illustration: A YOGI ON A BED OF SPIKES _An example of present-day austerities_ 17] Priests might also accumulate in heaven credit balances of Celestial power by undergoing penances for long periods. A heavy debt was also due to them by the gods for their sacrificial offerings. When a Brahman desired to exercise his accumulated power, he might even depose the deities, who were therefore placed under compulsion to fulfil his demands; his Celestial credit might exceed the “paying” possibilities of the supreme Powers. In the sacred tales Brahmans were credited with performing rigid penances for centuries.