All this was effected as mysteriously as though by magic.

At hearing the rattling in the throat of the captain, the soldiers who accompanied him had turned round, caught a glimpse of his extended arms, his eyes starting from their sockets, and then the torch fell and they were left in darkness.

From an unreflective, instinctive, mechanical feeling, the lieutenant cried: "Fire!" Immediately a volley of musketry flamed, thundered, roared in the cavern, bringing down enormous fragments from the vaults.

The cavern was lighted for an instant by this discharge, and then immediately returned to pitchy darkness rendered thicker by the smoke.

To this succeeded a profound silence, broken only by the steps of the third brigade, now entering the cavern..