My friend, who sometimes visits me in my summer solitude, is an artist by profession, a Scandinavian by birth, and a cosmopolitan by force of circumstances. We had dined at sunset; the sunset glow had reddened and faded again, and the evening purple steeped the vast chain of the mountains that embrace the deep gulf to eastward and rear themselves higher and higher toward the south. It was hot, and we sat at the landward corner of the platform, waiting for the night breeze to come down from the lower hills. The colour sank out of the air, there was a little interval of deep-grey twilight, and a lamp sent a yellow streak from the open door of the kitchen, where the men were getting their supper. Then the moon rose suddenly above the crest of the promontory, flooding the platform and lighting up every little spur of rock and knoll of grass below us, down to the edge of the motionless water. My friend lighted his pipe and sat looking at a spot on the hillside. I knew that he was looking at it, and for a long time past I had wondered whether he would ever see anything there that would fix his attention. I knew that spot well. It was clear that he was interested at last, though it was a long time before he spoke. Like most painters, he trusts to his own eyesight, as a lion trusts his strength and a stag his speed, and he is always disturbed when he cannot reconcile what he sees with what he believes that he ought to see. "It's strange," he said. "Do you see that little mound just on this side of the boulder?" "Yes," I said, and I guessed what was coming. "It looks like a grave," observed Holger. "Very true. It does look like a grave." "Yes," continued my friend, his eyes still fixed on the spot. "But the strange thing is that I see the body lying on the top of it. Of course," continued Holger, turning his head on one side as artists do, "it must be an effect of light. In the first place, it is not a grave at all. Secondly, if it were, the body would be inside and not outside. Therefore, it's an effect of the moonlight. Don't you see it?" "Perfectly; I always see it on moonlight nights." "It doesn't seem to interest you much," said Holger. "On the contrary, it does interest me, though I am used to it. You're not so far wrong, either. The mound is really a grave." "Nonsense!" cried Holger, incredulously. "I suppose you'll tell me what I see lying on it is really a corpse!" "No," I answered, "it's not. I know, because I have taken the trouble to go down and see." "Then what is it?" asked Holger. "It's nothing." "You mean that it's an effect of light, I suppose?" "Perhaps it is. But the inexplicable part of the matter is that it makes no difference whether the moon is rising or setting, or waxing or waning. If there's any moonlight at all, from east or west or overhead, so long as it shines on the grave you can see the outline of the body on top."