“La Divina Commedia,” Mantuae 1472, the first page of what is by many regarded as the oldest edition of the earliest known poem written in the Italian language. Now in the Bibliothèque Sainte Geneviève, Paris. PETRUS PEREGRINUS 46 “Epistola ... de Magnete.” _The earliest known treatise of experimental science._ Original photographic reproduction of first page of the almost illegible MS. No. 7378 A; page 67 _recto_ (embraced in a geometrical treatise), now in the Bibliothèque Nationale, Paris. PETRUS PEREGRINUS 52 Facsimile of Bodleian MS., No. 7027 (MS. Ashmole No. 1522), folio 186 _verso_, being Chap. II, Part II, of the “Epistola ... de Magnete,” wherein is described _the earliest known pivoted compass_. CHRISTOPHER COLUMBUS _Between_ 64 _and_ 65 Photographic reproduction of his letter, March 21, 1502, to Nicolo Oderigo, Ambassador to France and to Spain, which was acquired by the King of Sardinia and presented by him to the city of Genoa. It is now preserved in the Palace of the Genoese Municipality. CHRISTOPHER COLUMBUS _Between_ 64 _and_ 65 Translation of the letter written by him to Nicolo Oderigo, shown here on opposite plate; made into English by Mr. Geo. A. Barwick, B.A., of the British Museum. Permission to copy both the original letter and its translation was given by Messrs. B. F. Stevens and Brown, London. CECCO D’ASCOLI 524 Last page of the earliest known edition of his “Acerba,” Venetia, 1476. Printed nineteen times up to and including the edition of 1546. Now in the Bibliothèque Sainte Geneviève, Paris. LACTANTIUS 524 “De Divinis Institutionibus.” Page taken from the Sublacensi 1465 edition, called by Joannis Vogt _inter rariora typographiae incunabula rarissimum_. In the Bibliothèque Sainte Geneviève, Paris. PEDRO NUÑEZ 530 “Traitte que le docteur P. Nunes fit sur certaines doubtes de la Navigation.” Page 9 _verso_ of MS. Fr. No. 1338, now in the Bibliothèque Nationale, Paris. THE BIBLIOGRAPHICAL HISTORY OF ELECTRICITY AND MAGNETISM FROM B.C. 2637 TO A.D. 1821