PREFACE.

The Principal Work original: "Principale"; a massive, encyclopedic project envisioned by Bacon to encompass all knowledge, which remained unfinished. was projected by Bacon, but only in part executed. On these points, and on the bibliography of Bacon generally, Mr. Little’s Grey Friars in Oxford is of great value. Other works consulted will be noted as reference is made to them. Attention, however, may be specially called to Govi’s recent edition of the Latin translation of Ptolemy’s Optics original: "Optica", so frequently used by Bacon (Turin, 1885), a publication of the greatest value for the history of science; and to Heiberg’s edition of Euclid’s Optics original: "Optica" (vol. vii. of his edition of Euclid, Leipsic, 1895). Wuestenfeld’s History of Arabic Physicians original: "Geschichte der Arabischen Aerzte" (Göttingen, 1840), and Cantor’s History of Mathematics original: "Geschichte der Mathematik" (Leipsic, 1880–1892), throw light on the medieval men of science, Eastern or Western, mentioned by Bacon. Hauréau’s History of Scholastic Philosophy original: "Histoire de la Philosophie Scolastique" (Paris, 1872) defines, with some acerbity, Bacon’s position among the schoolmen Medieval academics who focused on logic, theology, and the reconciliation of faith with the philosophy of Aristotle.. Jourdain’s Critical researches on the Latin translations of Aristotle original: "Recherches critiques sur les traductions latines d'Aristote" (new edition, 1843) contain indispensable information as to the translators of whose shortcomings Bacon so often complains.

For the geographical section of the work, in addition to the classical works of Yule and Bunbury, frequent reference is made to the complete version of the travels of Rubruquis and Carpini William of Rubruck and Giovanni da Pian del Carpine were 13th-century Franciscan friars who traveled to the Mongol Empire and provided early Western accounts of the East., published by the Paris Geographical Society, in the fourth volume of their Collection of Voyages and Memoirs original: "Recueil de Voyages et de Mémoires" (1839).

As Seneca occupies so large a place in the seventh section of the Opus Majus, it may be mentioned that the edition used for this work is that of Haase (Leipsic, 1887). As to Aristotle, the references are to Didot’s edition (Paris, 1848–1873).

It remains for me to express my thanks to the Master and Fellows of Trinity College, Cambridge ; to