4 JEROME CARDAN. 



judicious matter 1 . He resolved then to edit a work, at 

 that time, I think, known only in manuscript, treating of 

 rays of light, and of the eye, of reflection, and of allied 

 topics, in the form of propositions proved by the aid of 

 geometrical diagrams, of which the original author was 

 John Peckham, Archbishop of Canterbury. This book, 

 which really deserved promulgation Peckham's Perspec- 

 tiva Communis* Fazio took upon himself, as he tells us 

 in the dedication to his own edition, the great labour of 

 correcting, a work heavy enough for a learned man, most 

 heavy therefore for him. It was an arduous undertaking, 

 he said, calling for great knowledge of mathematics pre- 



1 " Prospecti va Communi s d. Johannes Archiepiscopi Cantuariensis 



.... ad unguem castigata per Facium Cardanum." Milan, 



1480; p. 1 in the dedication. It begins thus: "In tanta laborura 

 cujuscunque generis copia, divino quodam imprimendi artificio com- 

 parata, appetentes hujus urbis impressores novi quidquam in medium 

 afierre quod esset studiosis non mediocriter profuturum : persuasique 

 rnea opera id effici posse : me illud efflagitantes convenerunt." 



2 John Peckham, Archbishop of Canterbury, born 1240, became a 

 minorite friar, and rose through sundry grades of Church preferment 

 to his crowning dignity. He bought it of the Pope for 4000 marks, 

 which afterwards he risked excommunication by not paying, or by 

 paying slowly. He was a man of taste, luxurious, accomplished in 

 the learning of the age, and liberal to all but Jews. The Jews he 

 persecuted. He died in 1292, and was buried in Canterbury Cathe- 

 dral. He left many .works which still exist in MS. Only two 

 have profited by the discovery of printing, namely, his Collectanea 

 Bibliorum, and his Perspectiva Communis. The last is interesting as 

 the first systematic work of the kind, and I find no trace of its having 

 passed out of MS. into print before it was published, with additions and 

 corrections, by Fazio Cardan. After that date it was re-issued fre- 

 quently by other editors at Leipsic in 1504, at Venice in 1505, and 

 afterwards at Nuremberg, and Paris, and Cologne. 



