An astronomer's assistant was fired for a one-second difference

Nevil Maskelyne dismissed his assistant Kinnebrooke in 1796 after noticing that he overestimated apparent speeds by 0.8 seconds. This discrepancy originated from a constant specific to each observer, revealing that nervous sensations were not instantaneous. Hermann Helmholtz later measured the speed of the nerve impulse at 25 m/s during experiments conducted between 1845 and 1850.