Where Tigris, at the foot of Paradise, Into a gulf shot under ground, till part Rose up a fountain by the Tree of Life. In with the river sunk, and with it rose, Satan, involved in rising mist; then sought Where to lie hid. Sea he had searched and land From Eden over Pontus, and the pool Maeotis, up beyond the river Ob; Downward as far antarctic; and in length West from Orontes to the ocean barred At Darien, thence to the land where flows Ganges and Indus. Thus the orb he roamed With narrow search, and with inspection deep Considered every creature, which of all Most opportune might serve his wiles, and found The serpent subtlest beast of all the field. Him, after long debate, irresolute Of thoughts revolved, his final sentence chose Fit vessel, fittest imp of fraud, in whom To enter, and his dark suggestions hide From sharpest sight; for in the wily snake Whatever sleights none would suspicious mark, As from his wit and native subtlety Proceeding, which, in other beasts observed,