ng by
a considerable space of time Descartes, who subsequently made use of a
like assumption in a like case.

How far this discovery of Ferrari's covered the rules given by Tartaglia
to Cardan, and how far it relieved Cardan of the obligation of secresy, is
a problem fitted for the consideration of the mathematician and the
casuist severally.[105] An apologist of Cardan might affirm that he cannot
be held to have acted in bad faith in publishing the result of Ferrari's
discovery. If this discovery included and even went beyond Tartaglia's, so
much the worse for Tartaglia. The lesser discovery (Tartaglia's) Cardan
never divulged before Ferrari unravelled 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 hypothesis 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, branded him as a liar and dishonest, and drove
Tartaglia almost wild with rage. That his offence did not meet with
universal reprobat