I began my career as a lawyer, but gave that up to teach mathematics...and gave that up to accept a commission in the French cavalry.
During the American Revolution, I commanded a frigate that was captured by the British.
After the war, I led France (and eventually the world) in establishing a weights and measure system based on decimal units.
I coined the term "metre" and helped determine its standard length relative to an arc of the meridian.
My other claim to fame is as a nautical astronomer, making improvements in instruments such as the quadrant and reflecting/repeating circles.
In hydraulics, I perpetuated the fallacy that a sphere and a hemisphere (with convex side upstream) will create the same resistent drag
in a fluid.
Jean Charles de Borda (1733 - 1799)