84 JEROME CARDAN 



wanted his forthcoming book to mark a new epoch in 

 this History of Mathematics, and that a change of 

 tactics was necessary. Alfonso d'Avalos, Cardan's 

 friend and patron, was at this time the Governor of 

 Milan. D'Avalos was a man of science, as well as a 

 soldier, and Cardan had already sent to him a copy of 

 Tartaglia's treatise on Artillery, deeming that a work of 

 this kind would not fail to interest him. In his first 

 letter to Tartaglia he mentions this fact, while picking 

 holes in the writer's theories concerning transmitted 

 force and views on gravitation. This mention of the 

 name of D'Avalos, the master of many legions and of 

 many cannons as well, to a man who had written a 

 Treatise on the management of Artillery, and devised 

 certain engines and instruments for the management of 

 the same, was indeed a clever cast, and the fly was 

 tempting enough to attract even so shy a fish as Niccolo 

 Tartaglia. In his reply to Jerome's scolding letter of 

 February 12, 1539, Tartaglia concludes with a description 

 of the instruments which he was perfecting : a square to 

 regulate the discharge of cannon, and to level and 

 determine every elevation ; and another instrument for 

 the investigation of distances upon a plane surface. He 

 ends with a request that Cardan will accept four copies 

 of the engines aforesaid, two for himself and two for the 

 Marchese d'Avalos. 



The tone of this letter shows that Cardan had at 

 least begun to tame the bear, who now seemed dis- 

 posed to dance ad libitum to the pleasant music of words 

 suggesting introductions to the governor, and possible 

 patronage of these engines for the working of artillery. 

 Cardan's reply of March 19, 1539, is friendly too 

 friendly indeed and the wonder is that Tartaglia's 

 suspicions were not aroused by its almost sugary polite- 



