卡尔·奥尔·冯·威尔斯巴赫1858—1929

Carl Auer von Welsbach (1 September 1858 – 4 August 1929), who received the Austrian noble title of Freiherr Auer von Welsbach in 1901, was an Austrian scientist and inventor, who separated didymium into the elements neodymium and praseodymium in 1885. He was also one of three scientists to independently discover the element lutetium (which he named cassiopeium), separating it from ytterbium in 1907, setting off the longest priority dispute in the history of chemistry.

He had a talent not only for making scientific advances, but also for turning them into commercially successful products. His work on rare-earth elements led to the development of the ferrocerium "flints" used in modern lighters, the gas mantle that brought light to the streets of Europe in the late 19th century, and the metal-filament light bulb. He took the phrase plus lucis, meaning "more light", as his motto.

Early life

Carl Auer was born in Vienna on 1 September 1858 to Alois Auer and his wife, Therese Neuditschka. He was the youngest of four children, his elder siblings being Leopoldine, Alois and Amalie. His father, ennobled in 1860 (as Alois Ritter Auer von Welsbach), was director of the Imperial printing office (K.-k. Hof- und Staatsdruckerei) in the days of the Austrian Empire.

Carl went to high schools in Mariahilf and Josefstadt. He attended the Realschule Josefstadt from 1873 to 1877, matriculating on July 16, 1877.

Next, he joined the Austro-Hungarian Army for one year of voluntary military service. He was commissioned as a Second Lieutenant.

Rare earths

Neodymium and praseodymium

In 1885, Auer von Welsbach used a method of fractional crystallization that he had developed himself to separate the alloy didymium into its two parts, for the first time. It had previously been believed to be an element. After 167 crystallizations, Auer von Welsbach differentiated it into two colored salts: he named the green colored salt "praseodymium" and the pink one "neodidymium".

He announced his achievement to the Vienna Academy of Sciences on 18 June 1885. His achievement was approved by Bunsen, but met with considerable skepticism from others.

Lighting innovations

Gas mantle

On 23 September 1885, Auer von Welsbach received a patent on his development of the gas mantle, which he called Auerlicht, using a chemical mixture of 60% magnesium oxide, 20% lanthanum oxide and 20% yttrium oxide, which he called Actinophor. To produce a mantle, guncotton is impregnated with a mixture of Actinophor and then heated, the cotton eventually burns away, leaving a solid (albeit fragile) ash, which glows brightly when heated. These original mantles gave off a green-tinted light and were not very successful, and his first company formed to sell them failed in 1889.

Radium research

For the rest of his life Auer von Welsbach turned again to "pure" chemistry. He worked largely on his estate at Welsbach Castle (Schloß Welsbach) near Treibach near Althofen. In addition to his work on elements and minerals, he made advances in the development of photographic techniques. He was also a devoted gardener, carefully supporting rare and difficult-to-grow plants in his garden, and breeding new varieties of roses and apple trees.

He published a number of papers on chemical separation and spectroscopy, working on radioactive elements as early as 1904.

Commemoration

In 2008 (150 years after his birth), Auer von Welsbach was selected as a main motif for a high-value collectors' coin: the Austrian €25 Fascination Light. The reverse has a partial portrait of Auer on the left-hand side. The sun shines in the middle of the green niobium pill, while several methods of illumination from the gas light from incandescent light bulbs and neon lamps to modern light-emitting diodes spread out around the silver ring.

He was also depicted on postage stamps of 1936, 1954 and 2012.

Awards and honors

1900, Elliott Cresson Medal, The Franklin Institute Awards, Philadelphia, PA, USA

1901, raised to the hereditary nobility by Franz Joseph I of Austria, with the title of Freiherr Auer von Welsbach

• 1920, Werner von Siemens Ring
• 1921, Wilhelm Exner Medal, inaugural awardee, Austrian Industry Association, Austria
• 1988, the Welsbach Museum at Althofen was opened in April, 1998
• 2011, National Inventors Hall of Fame, North Canton, Ohio, USA