250 JEROME CARDAN. 



I should wish you to show me the rule for those cases of 

 yours, as you have promised. 



NiCOLO. I am willing; but you should know, that in 

 order to be able on any sudden occasion to remember my 

 method of operation, I have reduced it to a rule in rhyme, 

 because, if I had not used this precaution, it would often 

 have escaped from my mind ; and although these rhymes 

 of mine are not very neat, I have not minded that, be- 

 cause it was enough that they served to bring the rule into 

 my memory whenever I repeated them. That rule I will 

 write for you with my own hand, in order that you may 

 be sure that my discovery is given to you fairly and 

 weU." 



The verses then follow which contain the rule for the 

 three case, a? 3 -J- bx z: c; # 3 bx -f- c and <*? 3 -}" c &# 

 discovered by Tartalea in 1534. Translated into the 

 language of modern mathematics, they read thus 1 : 



i The mystic rhymes themselves here follow. Tartalea's effusion 

 was a thing to puzzle Petrarch : 



" Quando chel cubo con le cose apresso 

 Se agualia & qualche numero discrete 

 Trouan dui altri different! in esso 

 Dapoi terrai questo per consueto 

 Ch'el lor produtto sempre sia eguale 

 Al terzo cubo delle cose neto 

 El residue poi suo generale 

 Belli lor lati cubi ben sottratti 

 Varra la tua cosa principale. 

 In el secondo de cotesti atti 



Quando chel cubo restasse lui solo 



