Gallium was discovered in 1875 by the French chemist Paul-Emile Lecoq de Boisbaudran, who first detected it by its spectral lines and then isolated the metal. Its name honours Gallia, the Latin name for France, though some suspected a hidden pun, since Lecoq means the cock and the Latin for cock is gallus. Gallium is a soft, silvery metal with the curious property of melting just above room temperature, so that it will liquefy in a warm hand. Liquid over most of the range of everyday temperatures, gallium has little structural use, but its compounds, above all gallium arsenide and gallium nitride, are vital semiconductors in light-emitting diodes, laser diodes, solar cells and high-frequency electronics.
Gallium's low melting point has made it a favourite of popular science demonstrations and novelty gifts: spoons cast from the metal appear solid at room temperature but dissolve into a puddle when used to stir a hot drink, a trick sturdy enough to have entertained chemistry classrooms for generations. In a more practical vein, gallium is a key component of Galinstan, a liquid alloy of gallium, indium and tin developed as a non-toxic replacement for mercury in thermometers and other instruments after mercury's health and environmental risks led many countries to restrict it.