"I do believe Monsieur Rossignol has been seized by some sudden mathematical insight," said Pontchartrain in a hushed voice. "It is said that Descartes’s great idea came to him in a sort of religious vision. I had been skeptical of it until this moment, for the very thought seemed blasphemous. But the look on Monsieur Rossignol’s face, as he cracked that cypher, was unmistakably like that of a saint in a fresco as he is drawn, by the Holy Spirit, into an epiphanic rapture."