cf. H. H. Brook, “The Warning Light” (ca. 1916)

I decided to call to him. Miss Baker had mentioned him at dinner, and that would do for an introduction. But I didn’t call to him, for he gave a sudden intimation that he was content to be alone — he stretched out his arms toward the dark water in a curious way, and, far as I was from him, I could have sworn he was trembling. Involuntarily I glanced seaward — and distinguished nothing except a single green light, minute and far away, that might have been the end of a dock. When I looked once more for Gatsby he had vanished, and I was alone again in the unquiet darkness.

–F. Scott Fitzgerald, The Great Gatsby