Madame Curie's Fireflies

Madame Curie and her husband, under extremely harsh conditions, refined the radioactive element 'radium'. On countless long and tiring experimental nights, the couple's favorite thing to do was to walk hand-in-hand into the pitch-black laboratory. At the time, they discovered that small glass test tubes containing radium would emit a soft and faint blue-green fluorescence in the dark. Madame Curie loved this dreamlike glow very much, and once gently wrote in her diary that these test tubes were like 'little sprites in the night sky' or 'fireflies on the ground'. The couple would sit quietly on wooden chairs, gazing at these beautiful, faint lights, enjoying their romantic moments together.