Search This Blog

Monday, 24 November 2014

163)The “25 Euro Silver-Niobium Coin Series”: (vi): 2003 onwards minted by the Austrian Mint:The Sixth coin in the Series: “Fascinating light” (2008):

163)The “25 Euro Silver-Niobium Coin Series”: (Part vi): 2003 onwards minted by the Austrian Mint by using Niobium and Niobium metal insertion technology for the first time anywhere in the World of Numismatics:  The Sixth coin in the Series: “Fascinating light” (2008):

Baron Karl Auer von Welsbach or Carl Auer, Freiherr von Welsbach (01.09.1858 – 04.08.1929):

Baron Karl Auer von Welsbach was an Austrian chemist and engineer who invented the gas mantle, which led to a greatly increased output of light by using Gas lamps. He was a brilliant chemist who was born in Vienna in 1858. He was a key figure in the development of gas lighting. The technology developed by Carl Auer van Welsbach is still in use in billions of light bulbs around the world today.

In 1885, he discovered and isolated the elements Praseodymium (green) and Neodymium (pink) – both Lanthanides bearing the atomic numbers 59 and 60 respectively on the Periodic Table of Elements, from a mixture called Didymium which was hitherto itself considered to be an element.

His interest in rare-earth elements led him to further discover that a fabric impregnated with a mixture of thorium nitrate and cerium nitrate could be made into a mantle that glowed brightly when heated by a gas flame. He patented the procedure and the resultant Welsbach gas mantle which he called “Auerlicht” and which was, in turn, developed by using a chemical mixture of 60% magnesium oxide, 20% yttrium oxide, which he called “Actinophor”, vastly improved gas lighting. To produce a mantle, guncotton is impregnated with a mixture of “Actinophor” and then heated, the cotton eventually burns away leaving a solid, though fragile, ash which glows brightly when heated.

These original mantles gave off a green-tinted light but were not very successful. In 1889, Welsbach’s first Company formed to sell these mantles wound up due to the failure of these mantles to become popular.

Not to be discouraged, in 1890, he introduced a new form of mantle based on a mixture of 99% thorium dioxide and 1% Cerium (IV) oxide. This mantle proved to be more robust and gave off a much whiter light.

 He successfully converted his advanced discovery into a commercially successful product and by 1891, his mantles were selling all over Europe.

He then researched on the development of metal-filament mantles, first with platinum wiring and then with Osmium. He developed a new method which mixed Osmium oxide powder with rubber or sugar into a paste, which was then squeezed through a nozzle and fired. The paste burnt away, leaving a fine wire of Osmium.

This was being positioned by him as the new mantle, but during this time electricity was introduced, therefore, Welsbach began to research methods to use the filaments as a replacement for the electric arc light.

In 1898, he succeeded in producing a metal filament light bulb which was a huge improvement on the existing carbon filaments of the day and lasted much longer by using about half the electricity for the same amount of light. Welsbach, thus, introduced the first metallic filament for incandescent lamps. Although the Osmium (atomic numbers 76 on the Periodic Table of Elements) that he used was considered to be too rare for general use, Welsbach’s improvements led to the development of the tungsten filament and the modern light bulb.

Today, although the incandescent lamp/bulb has greatly supplanted gas lighting, nevertheless, the gas mantle is still used widely in kerosene and other lanterns etc.

Welsbach is particularly well known for the development of Misch metal, a mixture of Cerium and other rare earth elements, which he combined with iron to make Auer’s metal, the first improvement over flint and steel for making sparks since ancient times.

In 1903, he registered another patent for a “fire striker” (Flint), having a composition named Ferrocerium, consisting of Pyrophoric alloys, i.e. 70% Cerium and 30% Iron which when scratched or struck would give off sparks. His advancement of the flint was used in modern cigarette lighters and, also, in strikers for lighting gas jets for the gas mantles which brought light to the streets of Europe in the late 19th century and led to the development of the filament light bulb. This system has remained in wide use in gas/petrol lighters today.

In 1907, he registered a company “Treibacher Chemische Werke GesmbH” to build and market this device.

For the rest of his life, he continued to publish a number of papers on chemical separation and spectroscopy which inspired several scientists to explore chemistry related solutions in various fields.

In 1922, he presented a major paper on his work on the separation of Radioactive elements.

The Silver-Niobium coin titled “Fascinating Light”:

This coin issued in 2008, also commemorates the 150th Birth Anniversary of  Carl Auer van Welsbach together with one of the earliest recognised energy sources – light.
 The Obverse of this coin shows a streetlight keeper involved in the maintenance/lighting up of a gas lamp/lantern outside Vienna’s neo-gothic city hall. He is shown as using a step-ladder which gives an impression of the considerable height at which the gas lantern is placed.  The ladder and one foot of the light-keeper as well as a portion of the pillar on which the lamp is placed spills over from the Niobium core onto the outer silver ring of the coin. These lamps were in use since 1800s in Vienna.

On the upper periphery of the coin is mentioned the name of the country “Republik Osterreich” (meaning the “Republic of Austria”). On the lower periphery is mentioned the denomination of the coin “25 Euro” and the year of issue “2008”.
 The Reverse of the coin is depicted the glowing Sun as the ultimate source of light, placed in the middle of this face of the coin and artificial light lamps placed in a manner which shows the evolution of lighting technology – several methods of illumination from the gas light to incandescent light bulbs and neon lamps to modern Light Emitting Diodes (LEDs), with the engravings spilling into the outer silver ring. This face also depicts a partial portrait of Welsbach on the left hand side.

The Niobium core on this coin has a green colour. This colour has been achieved by heat treating and oxidising the niobium core and applying an extra finish prior to its striking.

The specifications of the coin are:

Face value: 25 Euros; Metallic composition: Outer ring: Silver (Ag) 900 – 9 gms, Niobium 998 – 6.50 gms; Diameter: 34 mm; Weight: 16.50 gms; Edge: smooth.

Incandescent light bulb/lamp: This is an electric light produced with a wire filament heated to a high temperature by an electric current passing through it, until it glows – incandescence. The hot filament is protected from oxidation with a glass or quartz bulb that is filled with inert gas or evacuated. In a halogen lamp, filament evaporation is prevented by a chemical process that redeposits metal vapour onto the filament, extending its life. The light bulb is supplied with electrical current by feed-through terminals or wires embedded in the glass. Most bulbs are used in a socket which provides mechanical support and electrical connections. Incandescent bulbs are manufactured in a wide range of sizes, light output and voltage ratings say from 1.5 volts to about 300 volts and are used as table lamps, car headlamps, flashlights, in households, decorative and advertising lighting etc. Incandescent bulbs are much less efficient than most other types of electric lighting. They convert less than 5% of the energy they use into visible light while the remaining energy is converted into heat.

Neon Lamp: A neon lamp is a miniature gas discharge lamp which consists of a small glass capsule that contains a mixture of Neon and other gases at a low pressure and two electrodes (an anode and a cathode). When sufficient voltage is applied and sufficient current is supplied between the electrodes, the lamp produces an orange glow discharge. The glowing portion in the lamp is a thin region near the cathode. The larger and much longer neon signs are also glow discharges, but they use the positive column which is not present in the ordinary neon lamp. Neon glow lamps are widely used as indicator lamps in the displays of electronic instruments, appliances, advertisement hoardings etc.

Light Emitting Diodes (LED): this is a two-lead semiconductor light source. It is a basic pn-junction diode (this is a boundary or interface between two types of semi-conductor material, p-type and n-type, inside a single crystal of semi-conductor) which emits light when activated. When a voltage is applied to the leads, electrons recombine with electron holes within the device, releasing energy in the form of photons creating an effect called “electroluminescence” and the colour of the light (corresponding to the energy of the photon) is determined by the energy band gap (this is an energy range in a solid where no electron states can exist) of the semi-conductor.

The following coins have been issued in this Series:

2003 – 700 years old city hall in Tyrol or Tirol.

2004 – 150 years Semmering Alpine Railway

2005 – 50 years of Television

2006 – The European Satellite Navigation

2007 – Austrian Aviators

2008 – Fascinating light

2009 – Year of astronomy

2010 – Renewable Energy Sources.

2011 – Robotics

2012 – Bionics

2013 – Drilling tunnels


  1. Anand Varma has commented:
    "Kings and their kingdoms do not remain forever, but an invention of a scientist is an everlasting gift to mankind . Nice history of this great coin . Keep it up . Good study!!"

    1. Thank you so much, Anand. Much appreciate your encouragement. Your observation has a deep philosophical meaning, indeed!

  2. Krishna Tope has commented:
    "One of best coin information blog . Great job sir".

    1. Thank you so much for your encouraging comment, Krishna.