Japan's worst nuclear accident up to this date happened at Mihama. A pipe in the steam generator burst, leaking 55 tonnes of radioactive primary (reactor) coolant water into the secondary steam-generating circuit. Some radioactivity was released to the atmosphere and the plant's emergency core cooling system was activated. MITI reported later that the accident was caused by human error, some anti-vibration bars being wrongly installed by workers and sawn off short to make them fit. The release of radiation into the atmosphere was kept to a small amount. No deaths resulted. Various measures were taken to prevent the recurrence of the accident, including the replacement of the steam generators.

The daguerreotype photo process was announced at the French Academy of Science. Previous photographic processes required hours of exposure, but the daguerreotype (named after its inventor Louis Daguerre) needed only a few seconds. The plate was prepared with a layer of photo-sensitive silver halide, was exposed, developed using mercury vapor, and fixed in a solution of sodium hyposulphite. The image remains delicate, and must be protected under glass against damage by touching. The daguerreotype was produced with a direct positive image, needing no intermediate negative, but thus could not yield multiple reproductions made possible by later photographic processes.