CHAPTER XXII.
TUNNELS.
Subterranean London—The Mont Cenis Tunnel—Its Length— Ingenious Boring Apparatus—The Grotto of the Pausilippo— The Tomb of Virgil 237
TUNNELS.
Subterranean London—The Mont Cenis Tunnel—Its Length— Ingenious Boring Apparatus—The Grotto of the Pausilippo— The Tomb of Virgil 237