The Bronze Hand by Anna Katharine Green

But one resource was left: to warn Mr. S -- of his peril. This was not so easy a task as might appear. To make my story believed, I should be obliged to compromise Miss Calhoun, and Mr. S -- 's well-known chivalry, as far as women are concerned, would make the communication difficult on my part, if not absolutely impossible. I, however, determined to attempt it, though I could not but wish I were an older man, with public repute to back me.

Though there was but little in Mr. S -- 's public life which I did not know, I had little or no knowledge of his domestic relations beyond the fact that he was a widower with one child. I did not even know where he lived. But inquiry at police headquarters soon settled that, and in half an hour after leaving the doctor's office I was at his home.