In the mid-19th century, spectroscopy was being recognized as a new tool for the study of chemical elements. Each element has its characteristic spectrum. Spectroscopic studies also revealed the composition of Sun and other astronomical objects.
Sun was like a ‘chemical laboratory’ for the discovery of new elements. Helium was first discovered in this chemical laboratory, but during a total solar eclipse.
A French scientist Pierre-Jules-Cesar Janssen (1824-1907) was studying the properties and constituents of Sun. He had come to India to observe solar radiation emitted during a full ‘solar eclipse’ which was visible from Guntur (Andhra Pradesh, India) on 18 August 1868.
As visible light was completely cut-off during the eclipse, Janssen observed a new yellow faint line in the Photosphere of the Sun using a spectrophotometer. Observing it for the first time, Janssen named the ‘unknown’ line as D3 and assigned it to the presence of a new element in Sun.
The yellow spectral lines from the element Sodium were already designated by D1 and D2.
During the same time (nearly two months later) another scientist Norman Lockyer (1836-1920) in UK reported observation of a similar but faint D3 line in the spectrum even in the regular daylight.
Norman had established an astronomical observatory and Planetarium in 1913, also named as Norman Lockyer Observatory. He designated the observed line to a new element in Sun and named it as ‘Helium’ after Greek ‘Helios’ meaning the Sun. However, many uncertainties about its presence prevailed.
Although these two discoveries established the existence of a new element, but some considered it as a hypothetical element and others raised doubts about its terrestrial existence.
Further studies of astronomical objects however revealed the presence of Helium in other heavenly bodies. Helium was detected in the spectrum of star Cygnus and in Orion nebula. It became a topic of discussion in the scientific academies. Scientific deliberations continued to work out its nature which remained ‘an unexplained mystery’.
Considered as an element of sky, chemical actually looked at it as an unattractive substance as none of its compound could be established on Earth. Even when Helium was found on Earth much later, doubts were continued to be raised about its identity.
It was considered a substance somewhat analogous to Hydrogen. Eventually Helium was accepted in the Periodic Table as an entirely new elements.
The story of the discovery Helium on Earth actually began in 1895, almost thirty years after its existence was known in the Sun. Geologist H. Keyser in Germany first reported the presence of Helium in the gases emanating from hot springs at Wildbad in the Black Forest.
Such emanations from deep inside the Earth occur at certain places carrying hot fluids as well as hot gases. The observation of traces of Helium in them was an indication that Helium was present inside the Earth.
Almost during the same time, in 1895, Sir William Ramsay (1852-1916), a scientist in the UK, was studying a Uranium mineral called Uraninite and found that the gas emanating from its chemical reaction with sulphuric acid had a new element. He thought it could be both Neon and Helium.
Another scientist in Norway, Nils Abraham Langlet (1868-1936), a student of Per Theodor Cleve (1840-1905) while studying properties of a Norwegian rock called Cleveite, also containing Uranium, conclusively remarked that when Cleveite reacted with sulphuric acid, Helium was produced along with the other gases.
All these discoveries established the presence of Helium on Earth. Little was known about its origin, at what depth and where it could be found. Radioactivity was not discovered yet.
Terrestrial Helium has been found in beach sand on the sea coasts of Kerala in India (and also perhaps in Sri Lanka). The Kerala beach sand was known to be rich in monazite mineral, which is an ore of Thorium.
Thorium is a radioactive element like Uranium. Experiments were performed and techniques were developed to separate Helium from the monazite sand by vacuum distillation method. It appeared in the Journal of Chemical Education in 1930 and was described in the Popular Mechanics in its 1931 issue.
Helium so produced was sold in the market, and beach sand became a valuable commodity.
Thus, we can say that India had a significant role to play in these findings of Helium. First in the discovery of Helium in Sun, detected during a solar eclipse that could be seen from South India and then its production from Kerala beach sand.
But the story did not end here. Helium was existing in hot springs or monazite sand, but could not be produced in sizable quantity. Meanwhile, Sir William Ramsay was continuing his search for the other inert elements in Group 18B of Periodic Table.
He had already discovered Neon and was looking for other inert gases namely Krypton and Xenon. Sir Ramsay received the Noble Prize in 1904, the highest science award for his important discoveries.
The Big Question
So far larger quantities of Helium had been seen only in the extra-terrestrial bodies. On Earth it was found in smaller quantities in hot springs and monazite sand. The big question was – does Helium exist in larger quantity inside the Earth? The mystery unravelled unexpectedly.
During early 20th century, Natural gas was just beginning to be discovered in existing oil fields and new exploration wells. Prospecting wells were dig for exploration for oil and gas.
It was seen that Natural gas, which is mainly methane, occurred either independently or associated with oil in an oil well. The efforts were being made to collect the gas and utilize it as fuel.
In such a scenario in 1903, a Natural gas resource was discovered at Dexter in Kansas district of United States of America (USA). Any gas coming out from a well flows at a pressure, which is determined by its formation pressure.
The amount of gas that comes out in a particular time is measured as its ‘flow rate’. It was found that the Dexter well had high formation pressure and its flow rate measured as 200 cubic meters per day. This meant that 200 cubic meter gas was being produced in a day! It was quite high.
To celebrate the finding of a ‘big source of energy’, a District level ceremony was planned for its inauguration.
High dignitaries were expected to attend. The City Mayor was invited to ignite the fuel and light the ceremonial lamp. But, to everyone’s disappointment, the gas from the well could not be ignited!
The scientists had no option but to explore the reasons for it. The gas was tested in the laboratory and scientific analysis was carried out about the composition of the gas. Two years of intense studies finally led to complete analysis of the gas.
It was concluded that the emanations comprised different gases in larger quantities other than methane therefore it did not burn. It had large share of Nitrogen as much as 70 per cent of the total gas emanations. Methane was only 15 per cent. The remaining 15 per cent of the gas was made up of several gases in small quantities.
In 1905, the chemist, H.P. Cady (1874-1943), in his chemical laboratory at University of Kansas made a remarkable discovery, identifying the presence of Helium in the remaining gas mixture.
The exact share of Helium was estimated to be 1.84 per cent of the total gas content. It meant that 3.68 cubic meters of Helium was flowing per day. Big question has been answered. Even at this low percentage, enormous amount of Helium could be extracted because of the high flow rate of the Natural gas.
Although India had a role in the first detection of Helium and Europe made a significant contribution in the discovery of its terrestrial presence, the USA became the first country to recover Helium from Natural gas. Dexter gas finding had changed the fate of Helium. Natural gas became by far the major source of Helium on the Earth.
Little was known at that time about how to utilize the gas. C.W. Seibel a student of H.P. Cady, who dis his doctorate dissertation on Natural gas field surveys for finding Helium was feeling disappointed that his work has no practical application.
Gradually, its primary use developed as ‘lifting gases for bigger objects. It replaced Hydrogen in view of its immense advantage of non-flammability. The USA being the owner of Helium, planned to use it in Airships during the First World War. Hidden codes were used for Helium. For many years Helium remained a Military secret in USA.
In the Second World War, Helium regained uses both in airships and in water as patrolling blimps. During the period between two World Wars, it’s another major use developed in Cryogenics, a field of low temperature science and engineering.
Over the years as new Natural gas source became known around the globe, tests were conducted to locate the presence of Helium. More than a hundred gas fields have been tested. Simultaneously, considerable expertise has been gained in separation of Helium from the Natural gas.
Today we can say that most of current mining for Helium is carried out from Natural gas. Its other sources, i.e. hot spring, and rocks and minerals, have made a little contribution. As Helium started getting produced in substantial quantity, we learnt about its distinctive properties, and how Helium formed the basis for new scientific and technological applications.
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