Cardan shaft

The inventor who became best known for someone else's invention

Girolamo Cardano (Pavia, September 24, 1501 – Rome, September 21, 1576)

Every car has a cardan shaft, a drive shaft, a shaft that transmits the movement of the engine to the wheels, and it is named after the Italian doctor, mathematician and astrologer Girolamo Cardano.

How could someone who died more than four hundred years ago have come up with a part of the car?

Having traveled to Scotland from Milan to save the life of an archbishop, Cardano was known throughout Europe as a physician in the mid-16th century. However, his real passion was in mathematics.

He published a book in which he neatly listed the complete mathematical knowledge of his time, and he also casually advanced algebra a few more steps.

When he ventured into an autobiography (My Life) shortly before his death, he could proudly say that he had solved forty thousand mathematical problems and two hundred thousand smaller problems.

Cardano was convinced that everything in this existence could be captured in numbers. At the same time he believed in a personal demon, in a guardian angel, in the power of his aura, in his own clairvoyance and in messages from higher spheres.

For twenty-five years he played dice like crazy every day. Sometimes he was very rich and often penniless. He taught at all Northern Italian universities and wore the baldachin at the entry of Emperor Charles V in Milan, to name but a few.

He was always wonderfully contrarian: “I admit that among my evil inclinations there is one that occupies a special and great place, and to this I also continue to admit, namely, that I bring nothing with so much pleasure as what goes ill with my hearers.

Willingly and knowingly, I continue to hold on to this habit.' So he wrote at the age of 75. That's how he ended up in jail once. His beloved eldest son fed his wife an arsenic sandwich, received no mercy and was publicly beheaded.

A diplomatic Cardano might have prevented this.

One day he met a man from Bratislava who showed him a construction – the 'ring instrument' – consisting of three rings that fit together and were connected by pivots at right angles to each other.

This allowed the inner ring to remain horizontally balanced regardless of the position the outer ring took. Cardano wrote about it, as he wrote about everything, about the principle on which the cardan shaft rests.

Until the day of his death, he proclaimed - without shame - that he mainly strived for the survival of his name. He had sixty inventions to his credit. Should he be sure of eternal fame?

Ironically, his name went to a principle he had only written down.

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