for saloons where he could move at his ease.  There, also, Diderot would often delight his circle of admirers by the fluency and richness of his conversation, his friends extolling his disinterestedness and honesty, his enemies whispering about his cunning and selfishness.  The novelist Duclos, with his keen power of penetrating human character, would move leisurely through the throng, picking up material for his romances; and Mably would talk politics and drop ill-natured remarks.  The learned metaphysician Helvetius, too, was often there, seeking for compliments, his appetite for applause being voracious; so insatiable, indeed, that he even danced one night at the opera.  It was said that he was led to study mathematics by seeing a circle of beautiful ladies surrounding the ugly geometrician Maupertuis in the gardens of the Tuileries.  Dorat, who wasted his time in writing bad tragedies, and his property in publishing them; the gay, good-hearted Marmontel; Bernard—­called by Voltaire le gentil—­who wrote the libretto of “Castor et Pollux,” esteemed for years a masterpiece of lyric poetry; Rameau, the popular composer, in whose pieces Sophie always appeared; and Francoeur, the leader of the orchestra, were also among her guests.  J. J. Rousseau was the great lion, courted and petted by all.  When Benjamin Franklin arrived in Paris, where he was received with unbounded hospitality by the most distinguished of French society, he confessed that nowhere did he find such pleasure, such wit, such brilliancy, as in the salon of Mile.  Arnould.  M. Andre de Murville was one of the more noteworthy men of wit who attended her soirees, and he became so madly in love with her that he offered her his hand; but she cared very little about him.  One day he told her that if he were not in the Academie within thirty years, he would blow out his brains.  She looked steadily at him, and then, smiling sarcastically, said, “I thought you had done that long ago.”  Poets sang her praises; painters eagerly desired to transfer her exquisite lineaments to canvas.  All this flattery intoxicated her.  She wished to be classed with Ninon, Lais, and Aspasia, and was proud to be the subject of the verses of Dorat, Bernard, Rulhiere, Marmontel, and Favart.  Sophie’s wit never hesitated to break a lance even on those she liked.  “What are you thinking of?” she said to Bernard, in one of his abstracted moods.  “I was talking to myself,” he replied.  “Be careful,” she said archly; “you gossip with a flatterer.”  To a physician, whom she met with a gun under his arm, she laughed aloud, “Ah, doctor, you are afraid of your professional resources failing.”  Her racy repartees were in every mouth from Paris to Versailles, and she was in all respects a brilliant personage among the intellectual lights of the age.