Mr. Lanciani spoke last evening of the Police organizations of ancient and mediaeval Rome. He dwelt on the great hardships and dangers which these guardians of the peace were obliged to undergo. The streets of Rome were wholly without lights at night, and consequently were very favorable places for the operations of theives and foot-pads. The police, besides the ordinary duties of their office, were obliged to act as fire men. The frequency of disasterous fires in Rome is too well known to need comment. Mr. Lanciani closed his lecture as usual with appropriate stereopticon views.