Iron has the longest and most impressive history of the group 8 elements. It has been known and used for thousands of years, and has proved instrumental in the technological evolution of mankind. First smelted by the Hittites in about 2000 BC, it was widely used by Europeans in weapons and tools about eight hundred years later. The introduction of coke smelting in England in the eighteenth century allowed an increase in production of the metal, and was one of the factors that prompted the Industrial Revolution - it allowed, for example, a rapid expansion of the railway network. It has been widely used as a construction material: Europe's first iron bridge was built in Ironbridge, Shropshire in 1778-9, and the Eiffel Tower, completed in Paris in 1889, is made of wrought-iron.
Ruthenium and osmium are platinum metals and were discovered in samples of crude platinum; dissolving the metal in aqua regia produced residues which yielded the new elements. Ruthenium was discovered in 1844 by the Russian chemist, Karl Klaus, and osmium was discovered in 1803 by the British chemist, Smithson Tennant.
