Le Kain owed his success to him, and felt the warmest gratitude. "He is a faithful friend," he writes; "his temper is vehement, but his heart is good, and his soul sensitive and compassionate. Modest, in spite of the praises lavished on him by kings, by literary men, and by the rest of the world. Profound and just in his judgment on the works of others; full of amenity, kindness, and grace, in the intercourse of daily life, he was inflexible in his aversion to those who had offended him. He was an admirable actor. I have seen him put new life into the part of Cicero, in the fourth act of 'Rome Sauvée,' when we brought out that piece at Sceaux, in the August of 1750. Nothing could be more true, more pathetic, more enthusiastic, than he was in this part." Voltaire instructed the actors when they performed his own tragedies; his criticisms were just, and given with that earnestness and vividness of illustration that marked the liveliness of his sensations. "Remember," he said to an actor who whined out the part of Brutus, "remember that you are Brutus, the firmest of Romans, and that you must not make him address the god Mars as if you were saying, "O holy Virgin! grant that I may gain a prize of a hundred francs in the lottery." He insisted with mademoiselle Dumesnil that she should put more energy into the part of Mérope. "One must be possessed by the devil," said the actress, to declaim with such vehemence."--"You are right," said Voltaire; "and one must be possessed to succeed in any art."