Mercier, Barthelemi a learned French ecclesiastic and bibliographer, was born at Lyons April 4,1734. At the age of fifteen he became a novice among the regular prebendaries of the collegiate church of Saint-Genevieve, in Paris, and after one year of probation he was allowed to take the vow. Immediately thereafter he was sent to the Abbey of Chatrices, in Champagne, and there studied rhetoric and philosophy. In 1754 he was made assistant to the learned Perigre, librarian of Saint-Genevieve, and in 1760 was appointed his successor. Four years later Mercier was invested with the abbotship of Saint-Leger, which was then vacant, at Soissons. In 1772, in consequence of some trouble which he had with his associates, he resigned his functions as an abbot. Being thus liberated from official duties, he travelled through Holland and the Netherlands, where he was in hopes of collecting the materials necessary for the compilation of certain works on which he was engaged. Although he had yet published only the Supplement to the history of printing by Marchand he was warmly greeted wherever he went. In 1792 he was appointed a member of the so-called Monument Commission. In this capacity he exerted himself to rescue from destruction all private and public collections of art and literature. He also drew up for the use of librarians minute instructions touching the books intrusted to their custody, and a method for classifying them. Towards the latter part of his life Francois de Neufchateau, a clergyman and a fosterer of letters, granted him a pension of 2400 francs, the first annual installment of which was paid to him in 1798. - This assistance enabled Mercier to decline the generous offer of La Serna Santander, who had proposed to relinquish in favor of Mercier his own office of librarian at Brussels. He died in 1799. His writings are characterized by an evidence of profound erudition, together with system and perspicuity in all his researches. He published a large number of works, among which we may cite, Lettres sur la Bibliographie instructive de M. Debure (Paris, 1763, 8vo):Lettre sur le veritable auteur du Testament politique du Cardinal de Richelieu (Paris, 1765, 8vo; all of which were extracted from the memoires de Treveux):-Consultation sur la
question de savoir si les religieux de Sainlt-Genevieve sont onu ne sont pas Chanoines Reguliers (new ed. Paris, 1772, 4to).:-Opinion sur de pretendues propheties qu'on applique aux evenements presents (Paris, 1791):-Dissertations sur l'auteur de l'Imitation de Jesus-Christ, par l'abbe Ghesquiere (1775, 12mo). See Notice sur la vie etles ecrits de Mercier de Saint-Leger, by Chardon de la Rochette.