But this was only an infinitesimal part of their literary output. In his "Bibliothèque des écrivains de la compagnie de Jésus," which is itself a stupendous literary achievement, Sommervogel has already drawn up a list of 120,000 Jesuit authors and he has restricted himself to those who have ceased from their labors on earth and are now only busy in reading the book of life. Nor do these 120,000 authors merely connote 120,000 books; for some of these writers were most prolific in their publications. The illustrious Gretser, for instance, "the Hammer of Heretics," as he was called, is credited with two hundred and twenty-nine titles of printed works and thirty-nine MSS. which range over the whole field of erudition open to his times: archæology, numismatics, theology, philology, polemics, liturgy, and so on. Kircher, who died in 1680, wrote about everything. During the time he sojourned in Rome, he issued forty-four folio volumes on subjects that are bewildering in their diversity and originality: hieroglyphics, astronomy, astrology, medico-physics, linguistics, ethnology, horoscopy, and what not else besides. We owe to him the earliest counting-machine, and it was he who perfected the Aeolian harp, the speaking tube, and the microscope. We have chosen these great men merely as examples of the literary activity of the Society during the seventeenth and eighteenth centuries. Indeed, this inundation of books grew so alarming in its proportions that the enemies of the Church complained that it was a plot of the Jesuits who, being unable to suppress other books, had determined to deluge the world with their own publications.