274 JEROME CARDAN. 



and of existing rules the demonstrations were all his with 

 exception of four, said to have been left attached to his 

 four elementary rules by Mahomet ben Musa, and two of 

 which Lodovico Ferrari was the author. Cardan, in his 

 first chapter, ascribes to every man his own ; does honour 

 to Pisanus and Era Luca ; then, after coupling the dis- 

 covery of Scipio Ferreo with a high eulogy of the mathe- 

 matician and his divine art, Jerome adds: " In emulation 

 of him, Nicolo Tartalea of Brescia, our friend, when in 

 contest with the pupil of Ferreus, Antonia Maria Fior, 

 that he might not be conquered, discovered the same 

 rule, which he made known to me besought by many 

 prayers 1 ." He is nowhere chary of acknowledgment. In 

 the sixth chapter of this book he ascribes to Tartalea 

 the credit of having taught him in what way to push 

 forward all his algebraical discoveries, owning freely that 

 a hint given by Tartalea led to his use of the method by 

 which all the rules in the work are demonstrated, and all 

 that is new was first discovered. " When I understood," 

 he says, "that the rule taught to me by Nicolo Tartalea 

 had been discovered by him through a geometrical demon- 

 stration, I thought to myself that must be the golden way 

 up to all algebraical discovery 3 ." That golden way, there- 



1 Op. Tom, iv. p. 222. 



2 Ibid. p. 235. The details that have here been given are further 

 illustrated by a highly characteristic portrait of himself, prefixed by 

 Tartalea to his " Quesiti et Inventione." A fac-simile of that por- 

 trait, reduced in size, will be found upon the title-page of the second 

 volume of the present work. 



