JEROME CARDAN 9$ 



discovery included and even went beyond Tartaglia's, 

 so much the worse for Tartaglia. The lesser discovery 

 (Tartaglia's) Cardan never divulged before Ferrari un- 

 ravelled Giovanni Colla's puzzle ; but it was inevitable 

 that it must be made known to the world as a part of 

 the greater discovery (Ferrari's) which Cardan was in no 

 way bound to keep a secret. The case might be said to 

 run on all fours with that where a man confides a secret 

 to a friend under a promise of silence, which promise the 

 friend keeps religiously, until one day he finds that the 

 secret, and even more than the secret, is common talk of 

 the market-place. Is the obligation of silence, with which 

 he was bound originally, still to lie upon the friend, even 

 when he may have sworn to observe it by the Holy 

 Evangel and the honour of a gentleman ; and is the fact 

 that great renown and profit would come to him by 

 publishing the secret to be held as an additional reason 

 for keeping silence, or as a justification for speech? In 

 forming a judgment after a lapse of three and a half 

 centuries as to Cardan's action, while having regard both 

 to the sanctity of an oath at the time in question, and to 

 the altered state of the case between him and Tartaglia 

 consequent on Ludovico Ferrari's discovery, an hypo- 

 thesis not overstrained in the direction of charity may be 

 advanced to the effect that Cardan might well have 

 deemed he was justified in revealing to the world the 

 rules which Tartaglia had taught him, considering that 

 these isolated rules had been developed by his own 

 study and Ferrari's into a principle by which it would 

 be possible to work a complete revolution in the science 

 of Algebra. 



In any case, six years were allowed to elapse before 

 Cardan, by publishing Tartaglia's rules in the Book of 

 the Great Art, did the deed which, in the eyes of many, 



