#### John F. Hall

Caltech Seminar on History and Philosophy of Science

Wednesday, November 6, 2024 4:00 pm EST

Caltech

Dabney Hall of the Humanities

Pasadena, CA 91125

Parent was born in 1666 in France and died in 1716 at the age of 50. Trained in law, he preferred to study and write about scientific topics. He tutored to support himself and never had a position at a university. In 1699, because of an interest in mechanics, Parent was admitted as a student member to the French Academy of Sciences with the title of mechanician. He remained a student member until shortly before his death.

In spite of writing 5 books and on the order of 190 papers on a wide variety of subjects, Parent is known today only among a few historians, and just bits and pieces of his work are appreciated. His Wikipedia writeup consists of 9 lines of text and mentions some things about analytic geometry and beam theory. The MacTutor index, which contains biographies of over 3000 notable mathematicians, including 364 who were born in France, does not include Parent. Nor does he appear on other such lists of scientists or engineers.

The source material for Parent's work in mathematics consists of about 40 of his papers and a couple of his books. This talk will discuss some of the highlights while omitting the mathematical minutia: First person to construct a 3-dimensional coordinate system, to do calculus in 3 dimensions, to take a partial derivative, to solve a practical problem using a 3-dimensional coordinate system, to solve a practical problem by taking a partial derivative. Ingenious geometrical solutions for a honeycomb, polyhedra, problems in navigation and astronomy, and other examples. First to use a natural logarithm. First to use calculus to obtain optimal design solutions in engineering. Algorithm for error checking. Clever problems for teaching algebra.

Finally, although not the focus of the talk, some insight will be given into how Parent was viewed by his peers and why Parent is not better known today.

For more information, please contact Fran Tise by phone at 626-395-3609 or by email at ftise@hss.caltech.edu.