Gas Mantle - History

History

For centuries, artificial light has been generated using open flames. Limelight was invented in the 1820s, but the temperature required to produce visible light through black body radiation alone was too high to be practical for small lights. In the late 19th century several inventors tried to develop an effective alternative based on heating a material to a lower temperature but using the emission of discrete spectral lines to simulate white light.

Many early attempts used platinum-iridium gauze soaked in metal nitrates, but these were not successful because of the high cost of these materials and their poor reliability. The first effective mantle was the Clamond basket in 1881, named after its inventor. It was exhibited in the Crystal Palace exhibition of 1883. This device was made from a mixture of magnesium hydrate, magnesium acetate and water which was squeezed through holes in a plate to form threads, which were then moulded into a basket-shape and ignited. The acetate burned and the combustion products formed a matrix supporting the magnesium oxide which formed as the hydrate decomposed. This fragile structure was supported by a platinum wire cage and heated by a coal gas flame.

The modern gas mantle was one of the many inventions of Carl Auer von Welsbach, a chemist who studied rare earth elements in the 1880s and who had been Robert Bunsen's student. Ignaz Kreidl worked with him on his early experiments to create the Welsbach mantle. His first process used a mixture of 60% magnesium oxide, 20% lanthanum oxide and 20% yttrium oxide, which he called Actinophor, and patented in 1885.

These original mantles gave off a green-tinted light and were not very successful. Carl Auer von Welsbach's first company established a factory in Atzgersdorf in 1887 but it failed in 1889. In 1890 he discovered that thorium was superior to magnesium and in 1891 he perfected a new mixture of 99% thorium dioxide and 1% cerium dioxide that gave off a much whiter light and produced a stronger mantle. After introducing this new mantle commercially in 1892 it quickly spread throughout Europe. The gas mantle remained an important part of street lighting until the widespread introduction of electric lighting in the early 1900s.