Rousseau was barely sixteen when he began that roving existence which is so attractive to young people, so hateful in ripe age, and which lasted as long as his life.  Flying from his master whose brutality he dreaded, and taking refuge at Oharmettes in Savoy with a woman whom he at first loved passionately, only to leave her subsequently with disgust, he had reached the age of one and twenty, and had already gone through many adventures when he set out, heart-sore and depraved, to seek at Paris a means of subsistence.  He had invented a new system of musical notation; the Academy of Sciences, which had lent him a favorable ear, did not consider the discovery useful.  Some persons had taken an interest in him, but Rousseau could never keep his friends; and he had many, zealous and devoted.  He was sent to Venice as secretary to the French ambassador M. de Montaigu.  He soon quarrelled with the ambassador and returned to Paris.  He found his way into the house of Madame Dupin, wife of a rich farmer-general (of taxes).  He was considered clever; he wrote little plays, which he set to music.  Enthusiastically welcomed by the friends of Madame Dupin, he contributed to their amusements.  “We began with the Engagement temeraire,” says Madame d’Epinay in her Memoires:  “it is a new play by M. Rousseau, a friend of M. de Francueil’s, who introduced him to us.  The author played a part in his piece.  Though it is only a society play, it was a great success.  I doubt, however, whether it would be successful at the theatre, but it is the work of a clever man and no ordinary man.  I do not quite know, though, whether it is what I saw of the author or of the piece that made me think so.  He is complimentary without being polite, or at least without having the air of it.  He seems to be ignorant of the usages of society, but it is easy to see that he has infinite wit.  He has a brown complexion, and eyes full of fire light up his face.  When he has been speaking and you watch him, you think him good-looking; but when you recall him to memory, it is always as a plain man.  He is said to be in bad health; it is probably that which gives him from time to time a wild look.”

It was amid this brilliant intimacy, humiliating and pleasant at the same time, that Rousseau published his Discours sur les Sciences et les Arts.  It has been disputed whether the inspiration was such as he claimed for this production, the first great work which he had ever undertaken and which was to determine the direction of his thoughts.  “I was going to see Diderot at Vincennes,” he says, “and, as I walked, I was turning over the leaves of the Mercure de France, when I stumbled upon this question proposed by the Academy of Dijon:  Whether the advance of sciences and arts has contributed to the corruption or purification of morals.  All at once I felt my mind dazzled by a thousand lights, crowds of ideas presented themselves at once with