a true Christian to set them down for my
own use in cypher, so that after my death no one may be able to understand
them. If you will believe this promise, believe it; if you will not, let
us have done with the matter." "If I were not disposed to believe such
oaths as these you now swear," said Tartaglia, "I might as well be set
down as a man without any faith at all. I have determined to go forthwith
to Vigevano to visit the Signor Marchese, as I have now been here for
three days and am weary of the delay, but I promise when I return that I
will show you all the rules." Cardan replied: "As you are bent on going to
Vigevano, I will give you a letter of introduction to the Marchese, so
that he may know who you are; but I would that, before you start, you show
me the rule as you have promised." "I am willing to do this," said
Tartaglia, "but I must tell you that, in order to be able to recall at any
time my system of working, I have expressed it in rhyme; because, without
this precaution, I must often have forgotten it. I care naught that my
rhymes are clumsy, it has been enough for me that they have served to
remind me of my rules. These I will write down with my own hand, so that
you may be assured that my discovery is given to you correctly." Then
follow Tartaglia's verses:

"Quando chel cubo con le cose apresso
Se agualia a qualche numero discreto
Trouan dui altri differenti in esso
Dapoi terrai questo per consueto
Ch'el lor' produtto sempre sia eguale
Al terzo cubo delle cose neto
El residuo poi suo generale
Delli lor lati cubi ben sottratti
Varra la tua cosa principale.
In el secondo de cotesti atti
Quando chel cubo restasse lui solo
Tu osseruarai quest' altri contratti
Del numer farai due tal part 'a uolo
Che luna in l'altra si produca schietto
El terzo cubo delle cose in stolo
Delle qual poi, per commun precetto
Torrai li lati cubi insieme gionti
Et cotal summa sara il tuo concetto
Et terzo poi de questi nostri conti
Se solve col recordo se ben guardi
Che per natura son quasi congionti
Questi trouai, et non con passi tardi
Nel mille cinquecent' e quatro e trenta
Con fondamenti ben sald' e gagliardi
Nella citta del mar' intorno centa."

Having handed over to his host these rhymes, with the precious rules
enshrined therein, Tartaglia told him that, with so clear an exposition,
he could not fail to understan