I am a doctor of philosophy, not of medicine." "Then you may be a scientific expert," Harry hazarded.

"You are the expert here at the mine ?" "Not so," broke in Don Luis, gently.

"It is true that Carlos has some knowledge of chemistry, but he is not a mining expert.

He is my secretary, my man of affairs." "Oh, really the manager of the mine, then ?" pursued Harry.

"Pardon me if I ask too many questions.