How fast did Hermann von Helmholtz find that nerve impulses travel?

In 1850, Hermann von Helmholtz successfully measured the speed of a nerve impulse, demonstrating that it was a measurable physical process rather than a mysterious vital force. He found that the impulse travels at a speed of approximately 90 feet (27 meters) per second.1

This discovery was achieved through his invention of the myograph, an instrument that allowed for the precise experimental measurement of physiological functions.1