The element helium was first observed by a French astronomer Pierre-Jules-César Janssen (1824-1907) during the solar eclipse of 1868 in India. Pierre-Jules-César Janssen and other scientist travelled to India with the goal to observe the solar eclipse of Augustus 18, 1868. During the solar eclipse the scientists were using a portable spectroscope. The portable spectroscope had been improved by English astronomer Norman Lockyer (1836-1920) and Pierre-Jules-César Janssen. The scientists intended to make the first spectroscopic study of the Sun’s corona and they were astonished to detect a new yellow line (587.49 nm) in the solar spectrum. At those times the yellow line was impossible to create with known elements in the laboratory. The scientists recognised that the new yellow line belongs to an unknown element. Sir Norman Lockyer named the unknown element helium after helios (meaning sun in Greek). Since the discovery of helium on the sun, helium was considered as an element that might exist on the sun, but it presents on the Earth was unknown. In addition the scientists had doubts about the observation of helium. Nevertheless the search for helium on Earth was started. It was not until several years later that the presence of helium on Easth was finally demonstrated by Luigi Palmieri (1807-1896), an Italian volcanologist and meteorologist. Helium was detected during the spectral analysis of lava from Mt. Vesuvius in 1882. Finally, on March 26, 1895, the gas helium was discovered in uranium ore, cleveite by Sir William Ramsay (1852-1916) on Earth. Samples of the gas helium were sent by Sir William Ramsey to Sir Norman Lockyer and Sir William Crookes who identified helium. Sir William Ramsey (1852-1916), an English chemist has also discovered the noble gases neon, krypton and xenon. In addition helium was discovered by N.A. Langley and P.T. Cleve at 1895 in London, England and Uppsala, Sweden. Norman Lockyer and professor Edward Frankland proposed the name helium. In 1903, helium gas was found in a natural gas field in Dexter, Kansas. The concentration of helium was 1.84% in the field. Helium was likewise found in a number of other gas fields in American Great Plains with different concentrations, so there was enough quantities of helium available in the natural gas fields for extraction as byproduct of natural gas. The first helium extraction plant was built by United States Army in the country at Petrolia, Texas in 1915. The helium came from the natural gases of the Petrolia oil field, in Clay County. The Petrolia oil field contained 1% helium. Helium production declines after 1918 and the helium production stopped in 1929, when a better source was discovered north of Amarillo.