The Wednesday dinners of Mme. de Lambert were to her intimate friends, while every Tuesday afternoon she received a general circle which indulged in general conversation and read and discussed books which were about to be published; gambling, which seemed to be the principal means of entertaining in those days, had no place there. Fontenelle says: "It was, with very few exceptions, the only house which had been preserved from the epidemic of gambling--the only house where persons congregated simply for the sake of talking sensibly and with _esprit_. Those who had their reasons for considering it bad taste that conversation was still carried on in any place, cast mean reflections, whenever they could, against the house of Mme. de Lambert." In the evening, she received only a few select friends with whom she talked seriously. Her salon soon became the envy of those who were not admitted (and they were numerous), and was the object of many calumnies and attacks. During this time she found leisure to write two treatises of practical morality, _Avis d'une mère à son fils_, and _Avis d'une mère à sa fille_, which appeared without her permission. The manuscripts, lent to friends, fell into the hands of a publisher; and although the authoress endeavored to prevent the distribution of the works by buying up the entire editions, they were published outside of France. The two works written to her children form an important contribution to the educational literature of the time; in them the religion of the eighteenth century is first defined. "Above all these duties--civil and human (says the mother to her son)--is the duty you owe to the Supreme Being. Religion is a commerce established between God and man through the grace of God to man and through the duty of man to God. Elevated souls have for their God sentiments and a cult apart, which do not resemble at all those of the people; everything issues from the heart and goes to God." In these works, she attacked also the fad of free-thinking in vogue among the young men of the time. She was one of the few women of that age who could not separate themselves from reason and thought, even in religion; the latter was a matter for the reason and the intellect to decide, and was thus an elevated product of the mind rather than an instinct coming from the heart, or a positive revelation as it was in the seventeenth century. In this view, Madame de Lambert indicated the beginning of the later eighteenth-century spirit.