Period 6 element devices though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alcohol-filled, galinstan-filled, digital, or thermistor-based instruments. It remains in use in scientific research applications and in amalgam material for dental restoration. It is used in lighting: electricity passed through mercury vapor in a phosphor tube produces short-wave ultraviolet light which then causes the phosphor to fluoresce, making visible light. Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray other metal resembles tin but discolors when exposed to air. The
Willem van Heythuysen Posing with a Sword Willem van Heythuysen Posing with a Sword Willem van Heythuysen posing with a sword is a painting by the Dutch Golden Age painter Frans Hals, painted in 1625 and now in the Alte Pinakothek, Munich. It shows the Haarlem cloth merchant Willem van Heythuysen in a theatrical pose with a rapier. The painting shows a proud man standing in front of a neoclassical architectural element with drapery, leaning on a sword. In the distance a garden with a couple can be seen, and in the foreground some roses lie on the ground. It was first documented by Adriaan Loosjes, who