“And in Sprigg’s pockets—among his papers. . . ?”
“Not a thing. I’ve got all the stuff at the Bureau—a couple of ordinary letters, a few odds and ends of the usual kind. . . .” He paused as if suddenly remembering something, and pulled out a dog-eared note-book. “There was this,” he said unenthusiastically, handing a torn, triangular scrap of paper to Markham. “It was found under the fellow’s body. It don’t mean anything, but I stuck it in my pocket—force of habit.”
The paper was not more than four inches long, and appeared to have been torn from the corner of an ordinary sheet of unruled stationery. It contained part of a typewritten mathematical formula, with the lambda, the equals and the infinity sign marked in with pencil. I reproduce the paper here, for, despite its seeming irrelevancy, it was to play a sinister and amazing part in the investigation of Sprigg’s death.
Vance glanced only casually at the exhibit, but Markham held it in his hand frowning at it for several moments. He was about to make some comment when he caught Vance’s eye; and, instead, he tossed the paper to the desk carelessly with a slight shrug.
“Is this everything you found?”
“That’s all, sir.”
Markham rose.
“We’re very grateful to you, Captain. I don’t know what we’ll be able to make out of this Sprigg case, but we’ll look into it.” He pointed to the box of Perfectos. “Put a couple in your pocket before you go.”
“Much obliged, sir.” Pitts selected the cigars, and placing them tenderly in his waistcoat pocket, shook hands with all of us.