Thus when Monsieur Stangerson returned, he found the door of The Yellow Room closed, and his daughter in the laboratory, bending over her desk, at work!" Turning towards Monsieur Darzac, Rouletabille cried: "You know the truth! Tell us, then, if that is not how things happened." "I don't know anything about it," replied Monsieur Darzac.
"I admire you for your silence," said Rouletabille, "but if Mademoiselle Stangerson knew of your danger, she would release you from your oath.

She would beg of you to tell all she has confided to you.

She would be here to defend you!" Monsieur Darzac made no movement, nor uttered a word.

He looked at Rouletabille sadly.
"However," said the young reporter, "since Mademoiselle is not here, I must do it myself.

But, believe me, Monsieur Darzac, the only means to save Mademoiselle Stangerson and restore her to her reason, is to secure your acquittal." "What is this secret motive that compels Mademoiselle Stangerson to hide her knowledge from her father ?" asked the President.
"That, Monsieur, I do not know," said Rouletabille.