THE Zend-Avesta is the sacred book of the Parsis, that is to say, of the few remaining followers of that religion which feigned over Persia at the time when the second successor of Mohammed overthrew the Sassanian dynasty, and which has been called Dualism, or Mazdeism, or Magism, or Zoroastrianism, or Fire-worship, according as its main tenet, or its supreme God, or its priests, or its supposed f...