Faster we moved.

Louder grew the clangor of the drums, the gongs, the pipes.

Nearer came the walls; and ever more crowded with the swarming human ants that manned them.
We were close upon the heels of the last fleeing stragglers.

The Thing slackened in its stride; waited patiently until they were close to the gates.

Before they could reach them I heard the brazen clanging of their valves.