The doctor had deployed a net behind us—he called it a pelagic trawl—and as the morning’s faint breeze fattened the sails and we drew forward, the net fanned itself out in our wake, then sank from view. He said that he wanted to harvest what he could from the zone where the deep water of last night’s anchorage sloped up towards the shores of the island. This, he said, was the most fertile water of all.

A sea fog was descending, enclosing us in a claustrophobic embrace with the island.

We drew close and shapes separated themselves from the rock, heavy timbers on the steep shore. No beaches, not even a scree of boulders. The Connollys made soundings as we neared: twenty-six fathoms, twenty-one fathoms, twenty-eight, twenty-eight. The island was a pillar: it stood stark without preamble upon the ocean floor.

Movement: a man, three men. Climbing, as much as they were walking, on the steep terrain.

Fog closing in. They had noticed us, stopped, were staring. I could see beards, clothes that hung loose and dark on one. Another was naked: certainly a white man, but naked.

Another man, further up. The fog closed tighter.

We were looking now at a thin splinter of the island, in which the men were contained. The dark flanks of the rock had disappeared in the mist, as had everything but a narrow corridor of sea between us and the cliff. Argyle was concentrating at the helm, in a navy-blue serge dress tied off with a bow over his middle. He wore a plain bonnet and matching slippers, perhaps in response to the early morning chill on the deck. He was a wind-vane in the breeze, the loose ends of the bonnet ties and the bow rippling in the air.

The small noises of our approach were muffled in the blankness of the fog. The Connollys called the soundings at the volume of close speech, and the mist absorbed their voices. They heaved the dripping line into coils at their feet then threw the plummet again. As we neared the rocks, the numbers diminished. At four fathoms, the smothered sounds of the island were reaching us.

Beyond our gunwales now, mere yards of water led to the wall of white where the air had compressed into miasma: dense, wet and featureless. It did not move, as one expects mist to move on the sea. It was heavy as the seawater. The sails and the master’s ribbons had fallen slack. Dr Gideon beckoned to the Connollys and they abandoned their soundings to help him haul in the net: I could not watch, so transfixed was I by the closeness of the cliff and the suffocating fog.