The Science of the Shulba: A Study in Early Hindu Geometry c22.4

c22.4

*Configuration of the Vedi.*—A sacrificial altar is built in such a configuration as to place its principal line of symmetry always along the west-to-east direction. Hence it is also called the *prācī*, or "the eastward line." This line, as has been already observed, is of primary importance in the geometry of the *Sulba*. For all constructions are described in the *Sulba* invariably with reference to it. The sides of an altar lying on either sides of its *prācī*, whether parallel to it or not, are called its *pārśvamānī*, from *pārśva* = "side" and *māna* = "measure," and hence meaning literally the "side measure;" those which are at right angles to the *prācī* are called the *tiryaṅmānī* or the transverse measure," from *tiryak* = "transverse," *māna* = "measure." The latter term is oftentimes called in short *tiryak*, *tiraścīna* or *tiraścī* ("transverse") which are sometimes further abbreviated into *tiraḥ*. These terms are very old and occur in the earliest literatures of the Hindus.¹ The transverse sides are again distinguished into *paścāttiraścī* ("the western transverse side") and *purastāttiraścī* ("the eastern transverse side").² The former is also called the *mukha* (="the face") and the latter the *pada* (="the base") of the altar.