J. S. Fletcher,
The Markenmore Mystery — Chapter 23
(1923)
“ Guy Markenmore was murdered for the Spindler formula! Dead certain!"The Professor laughed again, and slapped his elegantly-gloved hand on the desk at his side. The two listeners stared at him, and then at each other. And this time it was Blick who spoke."Are we to understand, Sir Thomas," he asked, "that that formula was of great value?—of greater value than the three thousand pounds?""Call me Professor," said the famous scientist. "Saves time—— Yes. You are to understand that! Three thousand pounds! Had it been my secret, I wouldn't have sold it for thirty thousand pounds! ”
