Cardan was perhaps one of the most singular charac ters that has appeared in any age or country. In the ac count which he published of his own life, he has, with great ingenuousness, given a full detail of his good and bad qualities, though it is probable that he has suppress ed many facts which were by no means favourable to his moral reputation. Ile gravely informs his readers, that he had frequently determined to put himself to death ; that he often wandered all night in the streets ; that he took the greatest delight in bringing- forward subjects that were disagreeable to the company ; that he introduced every topic, whether it was connected or not with the subject of conversation ; that he ruined his family and his reputation by playing for whole days at games of chance ; and that he staked even his furniture and his wife's jewels.
At a time when astrology was in the zenith of its glo ry, it was natural that Cardan should follow the example of the most distinguished of his contemporaries ; but though we find in the character of the times a sufficient apology fur his devotion to judicial astrology, yet we seek in vain for any palliation of that empiricism and imposture, which he seems to have systematically pursued during the whole of his life. Ile who could seriously believe that he had the power of foretelling future events both in his dreams, and from particular marks upon his wails, must have been utterly devoid either of reason or intelligence ; but he who could commit such pretensions to writing, and try to impose upon posterity the same delusions which he had practised upon his contempora ries, must nave possessed a mind destitute of every ho nourable feeling, and so deeply in love with falsehood as to deceive when nothing could be gained by the deceit. Cardan, locked, seems to have been the most determined impostor of his times. Ile ascribed the extravagance of his opinions, and the eccentricities of his conduct, to the influence of the celestial bodies. Ile had the audacity to eatculate the nativity of our Saviour; and having foretold the time of his own decease, he is said to have starved himself to death, in order to verify the prediction.
The irregularities of conduct into which Cardan was continually hurried, by the violence and caprice of his temper, became the source of great misery and distress; and tile vices and misfortunes of his children, filled up the measure of his suffering-. his eldest son married a woman who possessed neither character nor fortune; and having killed her by poison, he was condemned to death, and executed in the prison at midnight. This distressing event produced a deep impression upon the 111111(1 of Cardan, who endeavoured to justify the murder on the ground of the wife's infidelity, and who maintain ed that the vengeance of heaven had followed the judges who pronounced sentence upon his son. Iris other sun was also au abandoned character, and his father was un der the necessity of throwing hint into prison, and of cuting off one of his ears, and disinheriting him. The payment of his daughter's dowry, and the circumstance of her having no children, were the only distresses which she occasioned.
From such a degrading picture, it is pleasing to turn to those marks of genius and talents by which Cardan has perpetuated his name. As a philosopher, he is en titled to no praise, and as a medical writer he is chiefly famed for his industry and fidelity in the collection of facts. The philosophical speculations which he has pub lished in his works Dr subtilitate and Be Varietate rerun, are the mere ravings of an unfettered imagination; and if arguments were wanting to prove that Cardan labour ed under a partial insanity, we should appeal to these works, as well as to the whole of his conduct.
As a mathematician, however, the merits of Cardan arc beyond all praise. In the year 1589, he had com pleted nine books on arithmetic, algebra, and geometry, under the title of Libel. magna ; and when it was nearly printed, having heard accidentally of Tartalea's discoveries in cubic equations, he was extremely anxious to obtain these discoveries for insertion in his work. Cardan first applied to Tartalea through the medium of a bookseller, and, along with the most flattering com pliments, he sent him a number of questions to resolve. Tartalea, however, refused to disclose his rules, which Cardan again attempted to obtain from him by personal correspondence. Finding every effort unsuccessful, Cardan at last endeavoured to gain by cunning what he could not acquire by the most urgent supplication. lie wrote to Tartalea, that he had recommended him to his particular friend and pati on the Marquis del Vasto, who was very anxious to see him ; and he invited hint to spend a few days with him at Milan, accompanying the invita tion, however, with a distinct notification, that such visit might be useful to Tartalea, and that it would be dangerous to offend the Marquis by a refusal. lore intimidated by the threat, than allured by the invitation. Tartalea set out for Milan ; but as the Marquis had gone to Vigevano before his arrival, he was induced to spend three days with Cardan till the Marquis should return. Cardan employed every artifice to obtain from his guest the secret for which he so ardently longed. I shall swear to you," says he, " on the holy evangelists, and by the honour of &gentleman, not only never to publish your inventions, if vou reveal them to me; but I also promise to you, and pledge my fait. as a true Christian, to note them down in cyphers, so that after my death no other person may be able to understand t tem." To these protestations Tartalea replied, " If 1 refuse to ;;iv e credit to these assurances, I should deservedly be ac counted utterly void of beliel , hut as 1 intend to rude to Vigevano to sec his excellency the Marquis, as I have been here now these three days, and am weary of wait ing so long; whenever I return. therelore, I promise to shew you the whole." Card,..n, howeser, having re newed his entreaties to obtain the rule before the depar ture of his friend, Tanaka " I am content; but you must know, that to he able on all occasions to re member such °jut:rations, I nave brought tee rule into rhyme; for if I had not used that precaution, I should often have forgot it ; and though my rhy,•,es are not very good, 1 do not value that, as it is sufficient that they serve to bring the rule to mind as often as I repeat them. I shall here write the rule with my own hand, that you may be sure I give you the discovery exactly." These ernes contained the rule for the three cases Tartalea reminded Cardan, at parting, of his obligation to secrecy ; and during a subsequent correspondence, in which the latter proposes some difficulties in the solu tion of cubic equations, Tartalea displays the greatest suspicion that Cardan would betray the secret, and never fails to remind him of the vow which he had made.