[104] Montucla, Histoire de Math. i. 596, gives a full account of Ferrari's process.
[105] In the De Vita Propria, Cardan dismisses the matter briefly: "Ex hoc ad artem magnam, quam collegi, dum Jo. Colla certaret nobiscum, et Tartalea, à quo primum acceperam capitulum, qui maluit æmulum habere, et superiorem, quam amicum et beneficio devinctum, cum alterius fuisset inventum."—ch. xlv. p. 175.
[106] Prefixed to the De Vita Propria.
[107] In a question of broken faith, Cardan laid himself open especially to attack by reason of his constant self-glorification in the matter of veracity.
[108] Leonardo knew that quadratic equations might have two positive roots, and Cardan pursued this farther by the discovery that they might also have negative roots.
[109] "Caput xxviii. De capitulo generali cubi et rerum æqualium numero, Magistri Nicolai Tartagliæ, Brixiensis—Hoc capitulum habui à prefato viro ante considerationem demonstrationum secundi libri super Euclidem, et æquatio hæc cadit in
. cu v binomii ex genere binomii secundi et qunti m̃.
. cuba universali recisi ejusdem binomii."—Opera, tom. iv. p. 341.