Cobalt blue
Cobalt blue in impure forms had long been used in Chinese porcelain, but it was independently discovered as a pure alumina-based pigment by Louis Jacques Thénard in 1802. Commercial production began in France in 1807. The first recorded use of "cobalt blue" as a color name in English was in 1777. The leading world manufacturer of cobalt blue in the 19th century was Benjamin Wegner's Norwegian company Blaafarveværket ("blue colour works" in Dano-Norwegian). Germany was also famous for production, especially the blue colour works ("Blaufarbenwerke") in the Ore Mountains of Saxony.
Blue
Blue was the colour of liberty and revolution in the 18th century, but in the 19th it increasingly became the colour of government authority, the uniform colour of policemen and other public servants. It was considered serious and authoritative, without being menacing. In 1829, when Robert Peel created the first London Metropolitan Police, he made the colour of the uniform jacket a dark, almost black blue, to make the policemen look different from soldiers, who until then had patrolled the streets. The traditional blue jacket with silver buttons of the London "bobbie" was not abandoned until the mid-1990s, when it was replaced by a light blue shirt and a jumper or sweater of the colour officially known as NATO blue.