her (Aitareya Brahmana 1-7 and the Taittiriya Samhita vi 1-5-1,). The story begins with the statement that the Sacrifice (the mysterious Sacrificial personage) went away from the Gods. The Gods were then unable to perform any further ceremonies, and did not know where it (the sacrifice) had gone to; and it was Aditi that helped them in this state, to find out the proper commencement of the sacrifice. This clearly means that before this time sacrifices were performed at random, but it was at this time resolved and fixed to commence them from Aditi. Aditi was thus the oldest and rst commencement of the sacrifice or the year. In the Vajasaneyi Samhita 4-19 Aditi is said to be Ubhayatah Shirshni "double-headed" and the commentators interpret it to mean that the two termini of the sacrifice which began and ended with Aditi, are the two heads here alluded to. These traditions are further corroborated by the sacrificial ceremonies. According to the sacrificial terminology, the 4th day before Vishnu-van or the central day of the yearly Satra is called the Abhijit day. Now if Abhijit day be supposed to be named after the Nakshtra of that name (i.e. when the Sun is in Abhijit) then the Vishnu van or the autumnal equinox must fall four days after the asterism of Abhijit; and it can be shown by astronomical calculation that with Aditi or Punarvasu at the Vernal equinox to commence the sacrifice, we nearly get at the same result.
Therefore, the oldest period in the Aryan civilisation may be called the Aditi or the pre-Orion period and we may roughly assign 6000—4000 B.C. as its limits. Then there was the Orion period roughly extending
