Juve drew a pencil from his pocket and scratched off a fine dust of graphite which he shook over the paper. Gradually the outline of a hand appeared, faint, but quite visible.
"That is how," resumed Juve, "with this very simple process, you can decipher the finger prints of persons who have written or rested their hands on anything—paper, glass, even wood. According to the clearness of this outline which is thrown up by the coagulation of the plumbago—thanks to the ordinary moisture of the hand—which was laid on the paper, I can assure you that some one wrote on Lady Beltham's desk about ten days ago."
"It is wonderful," said Fandor. "Here, then, is proof positive that her Ladyship visits her house from time to time."
"Correct—or at least that some one goes there, for that is a man's hand."
"Well, what are you going to do now, Juve?"
"Now? I'm off to the Prefecture to get rid of my false embonpoint, which bothers me no end. I have never been so glad that I am not naturally stout."
Fandor laughed.
"And I own to you that I shan't be sorry to get rid of my false moustache. All the while I was inspecting that cursed house, this moustache kept tickling my nose and making me want to sneeze."
"You should have done so."
"But suppose my moustache had come off?"