23.11–15

Other islanders then appear, all with lumps of burning slag to throw at the ship, and they keep going back to their forges for more ammunition.  The island looks like it's on fire, and the sea around them boils like a pot of boiling meat.The monks can still hear the cries of the islanders, and they smell the stench of the fires.  Brendan urges them to be brave, because they're on the borders of Hell.

[11] At vērō vir Deī ... ubi cecidit massa: “nominative absolute” or anacolouthon; perhaps the most dramatic example in the Navigatio.

quasi spatium ūnīus mīliāriī: for the accusative see 23.9.

[12] alter super alterum: “one on top of other," i.e., “one after the other”; CL would probably be alius super alium. I don’t see the significance of this detail, though it does make the story more vivid.

iactābant suam massam: we might have expected iactābant suās massās.

revertentēs in illōrum officīnās, incendentēs eās: they returned to their workshops and restarted or revived the workshop fires.

[13] sīcut ūnus globus: “like a ball (of fire).”

bene ministrātur ab igne: CL would be bene ministrātur igne (ablative of means).

[14] audiēbant: sc. Brendānus et frātrēs.

ad aurēs ... habitantium in illā: = ululatus habitantium in illā (īnsulā) adhūc attingēbat aurēs eōrum.

adhūc: is important; even though the island was out of sight, they could still hear the wailing of its inhabitants.

[15] rōborāminī: probably imperative.

in cōnfīnibus īnfernōrum: “on the borders of hell”; note Matthew 16.18: “And I say to thee that thou art Peter, and upon this rock I will build my church, and the gates of hell (portae inferi) shall not prevail against it.”