Lockyer, Joseph Norman

Helium - the atomic number is 2 and the chemical symbol is He. The name derives from the Greek helios for sun . The element was discovered by spectroscopy during a solar eclipse in the sun s chromosphere by the French astronomer Pierre-Jules-Cesar Janssen in 1868. It was independently discovered and named helium by the English astronomer Joseph Norman Lockyer. It was thought to be only a solar constituent until it was later found to be identical to the helium in the uranium ore cleveite by the Scottish chemist William Ramsay in 1895. Ramsay originally called his gas krypton, until it was identified as helium. The Swedish chemists Per Theodore Cleve and Nils Abraham Langet independently found helium in cleveite at about the same time. 

Sir Joseph Norman Lockyer, 1836-1920. Director of the solar physics observatory of The Royal College of Science at South Kensington. Pioneer in the spectroscopy of the sun and stars. In 1868 Lockyer and Janssen independently discovered a spectroscopic method of observing the solar prominences in daylight. Such observations had previously been made only at the time of total eclipses of the sun. 

But no one had ever subdivided a hydrogen atom, nor had they convincingly transmuted one element into another. So why credit this untested idea In the 1870s, the astronomer Joseph Norman Lockyer suspected that it was simply a question of finding the right conditions. Lockyer proposed that to transmute elements you needed the fiery furnace of a star. 

In 1868, a total solar ecHpse provided a unique oppoitunity to apply the spectroscope to stellar chemistry. At the moment when the Sun was perfectly eclipsed, the solar prominences surrounding the dark disk provided discrete line-emission spectra. Among these was a series of lines that matched no known elements. The discoverer, Joseph Norman Lockyer (1836-1920), postulated the existence of a new chemical element, helium after Helios (or Sun). The names of most metals typically end in ium or um and since most elements are metals hehum was first assumed to be a metal and named accordingly. Some 27 years later, helium was identified as a gas emanating from the uranium-containing mineral cleveite by William Ramsay. 

Soon afterwards Ramsay discovered a second new gas by heating the mineral cleveite. The spectrum of this gas showed a line coincident with a Fraunhofer line that been observed in the solar spectrum in 1868 by the astronomer Joseph Norman Lockyer (1866-1920) Since the line was not shown by any element known on earth, Frankland had named it helium after the Greek helios meaning sun. Ramsay found that his terrestrial helium was as unreactive as argon. 

A pioneer of thermochemistry, Julius Thomsen was first and foremost an experimentalist. Yet he also had an interest in chemical theories, and he was the only Danish scientist who, until Bohr in 1913, actively examined and contributed to the understanding of the periodic system. As mentioned, ever since the 1860s he entertained the heterodox view that the atoms of chemistry are complex particles and that this is revealed by regularities in their atomic weights. Of course, he was far from the only neo-Proutean of his time, but he was one of the most distinguished and articulate advocates of the idea of a basic unity of matter. In a work of 1887 he connected for the first time this idea with the periodic system, undoubtedly inspired by an address that William Crookes (1832-1919) had given the year before to the British Association for the Advancement of Science.Another likely inspiration was the British astronomer Joseph Norman Lockyer (1836-1920), whose work on the cosmic evolution of the elements had a great deal of similarity with the views expounded by Thomsen. 

---