1821-08-31

Switch to the dark mode that's kinder on your eyes at night time.

Switch to the light mode that's kinder on your eyes at day time.

Switch to the dark mode that's kinder on your eyes at night time.

Switch to the light mode that's kinder on your eyes at day time.

This Day in History: 1821-08-31

Happy Birthday! (August 31, 1821)
Hermann von Helmholtz, German physician and physicist.
photo source: wikimedia.org