κολυμβήθραν. The pool or piscina was deep enough for total immersion, and large enough for many to be baptized at once. Cf. Bingh. Ant. VIII. vii. 2; XI. xi. 2, 3. For engravings of the very ancient Baptisteries at Aquileia and Ravenna, shewing the form of the font or piscina, see Dict. Christian Ant. “Baptistery.”