72 JEROME CARDAN 



which may be regarded as an early essay in advertising. 

 He was fully convinced that his works were valuable and 

 quite worth the sums of money he asked for them ; the 

 world was blind, perhaps wilfully, to their merits, there- 

 fore he now determined that it should no longer be able 

 to quote ignorance of the author as an excuse for not 

 buying the book. This appendix was a notification to the 

 learned men of Europe that the writer of the Practice of 

 Arithmetic had in his press at home thirty-four other 

 works in MS. which they might read with profit, and that 

 of these only two had been printed, to wit the De Malo 

 Medendi Usu and a tract on Simples. This advertise- 

 ment had something of the character of a legal docu- 

 ment, for it invoked the authority of the Emperor to 

 protect the copyright of Cardan's books within the 

 Duchy of Milan for ten years, and to prevent the intro- 

 duction of them from abroad. 



The Arithmetic proved far superior to any other 

 treatise extant, and everywhere won the approval of the 

 learned. It was from Nuremberg that its appearance 

 brought the most valuable fruits. Andreas Osiander, 1 a 

 learned humanist and a convert to Lutheranism, and 

 Johannes Petreius, an eminent printer, were evidently 

 impressed by the terms of Cardan's advertisement, for 

 they wrote to him and offered in combination to edit 

 and print any of the books awaiting publication in his 

 study at Milan. The result of this offer was the reprint- 

 ing of De Malo Medendi, and subsequently of the tract on 

 Judicial Astrology, and of the treatise De Consolatione ; 

 the Book of the Great Art, the treatises De Sapientia 

 and De Immortalitate Animorum were published in the 



1 There is a reference to Osiander in De Subtilitate, p. 523. 

 Cardan gives a full account of his relations with Osiander and 

 Petreius in Opera, torn. i. p. 67. 



