I first learned of William Sloane's work from an article about "weird mysteries" I read in college. I'll be damned if I remember the author or the book it was in, but I did copy down a list of titles and authors that I still have somewhere. And that was over twenty years ago. Sheesh.
The cover looks promising, but the lurid promise isn't carried out too well. (The edition I have is a 1967 paperback; the novel itself was published in 1937.) The story is the account of Richard Sayles, a college professor from New York, who visits a former colleague in an isolated house in coastal Maine. His friend, Julian Blair (rather Dark-Shadows-ish, that) has been engaging in some strange, secretive experiments. He just hasn't been himself since his beloved wife died, y'see. And staying with him are his young sister-in-law and the surly, arrogant, and mysterious Mrs. Walters.
The foreshadowing is laid on thick in the opening chapters. There's a lot of "had I but known!" stuff going on, and several paragraphs are dedicated to breathless, purple gloom-and-doom prose. He writes of the town near the house, "How can they look down their own streets and across the river to the point where Julian's house once stood without feeling the hairs lift on the backs of their necks?" Yeesh.