Next moment I stopped short, brought up by a shock which spilled the excitement through my bowels like water. Something had moved in the murk, just to my right.

I froze still, straining my eyes to see. There was no movement.

I held my breath, listening. There was no sound. I flared my nostrils, testing the air cautiously round me. There was no smelly animal or human; the cave smelt, I thought, of smoke and damp rock and the earth itself, and of a queer musty smell I couldn’t identify. I knew, without putting it into words, that had there been any other creature near me the air would have felt different, less empty. There was no one there.

I tried a word, softly, in Welsh. “Greetings.” The whisper came straight back at me in an echo so quick that I knew I was very near the wall of the cave, then it lost itself, hissing, in the roof.

There was movement there—at first, I thought, only an intensifying of the echoed whisper, then the rustling grew and grew like the rustling of a woman’s dress, or a curtain stirring in the draught. Something went past my cheek, with a shrill, bloodless cry just on the edge of sound. Another followed, and after them flake after flake of shrill shadow, pouring down from the roof like leaves down a stream of wind, or fish down a fall. It was the bats, disturbed from their lodging in the top of the cave, streaming out now into the daylight valley. They would be pouring out of the low archway like a plume of smoke.

I stood quite still, wondering if it was these that had made the curious musty smell. I thought I could smell them as they passed, but it wasn’t the same. I had no fear that they would touch me; in darkness or light, whatever their speed, bats will touch nothing. They are so much creatures of the air, I believe, that as the air parts in front of an obstacle the bat is swept aside with it, like a petal carried downstream. They poured past, a shrill tide of them between me and the wall. Childlike, to see what the stream would do—how it would divert itself—I took a step nearer the wall. Nothing touched me. The stream divided and poured on, the shrill air brushing both my cheeks. It was as if I did not exist. But at the same moment when I moved, the creature that I had seen moved, too. Then my outstretched hand met, not rock, but metal, and I knew what the creature was. It was my own reflection.

Hanging against the wall was a sheet of metal, burnished to a dull sheen. This, then, was the source of the diffused light within the cave; the mirror’s silky surface caught, obliquely, the light from the cave’s mouth, and sent it on into the darkness. I could see myself moving in it like a ghost, as I recoiled and let fall the hand which had leapt to the knife at my hip.