Page:The Scientific Monthly vol. 3.djvu/250

 244 THE SCIENTIFIC MONTHLY

was the real nitxogen and that chemical nitrogen was lighter becanee of the presence of some lighter substance mixed with it^ but tins opinion was proved to be incorrect. Then it was suggested that pee- sibly atmospheric nitrogen was heavier^ because some of the molecules contained more atoms than real nitrogen. There is pretty good proof that the molecules of nitrogen consist of two atoms; the suggestion was that atmospheric nitrogen might contain a certain percentage of molecules consisting of three or four atoms. It has been long known that electric discharges through oxygen produce an effect of this kind. Part of the oxygen is converted into ozone^ which is denser^ so that the same volume would have greater weight. It was proved, how- ever^ that no similar phenomenon occurs with nitrogen.

At this stage Professor Samsay joined forces with Lord Bayleigh and, by passing nitrogen obtained from air through a red-hot tube con- taining magnesium, he found that, though most of the gas combined with the magnesium, a small portion did not do so, though the process was continued for ten days. This small portion was about one eighty- fourth of the whole. When chemical nitrogen was subjected to the same treatment it was entirely absorbed.

Lord Bayleigh repeated under more favorable conditions and vnith larger quantities of air. Cavendishes experiment of passing sparks through a mixture of air and oxygen and got a gas identical with that obtained by Bamsay. This gas is heavier than nitrogen in the ratio of ten to seven. Many experiments have been tried, but without success, to make it combine with other substances. It is inert, hence the name argon from the Greek word with that meaning. It has no chemistry — ^all the experiments possible with it are physical. Its inert^ ness kept it a long time undetected. Its inertness makes it of no chemical value now that it has been found, except in so f ar afi its inertness may affect chemical theory. Bamsay, having found argon in the air looked about for some other source. While doing so he received a letter from Miers, the mineralogist, at that time connected with the British Museum, who suggested that it might be well to examine some uraninites (varieties of pitchblende largely uranium oxide). Hillebrand, one of America's most noted analysts, had obtained a gas from uraninite which he supposed to be nitrogen. Bamsay thought it improbable that Hillebrand's methods would pre- pare nitrogen from any of its compounds and he reexamined one of the minerals used by Hillebrand, namely, clfevite. He did not find argon, but he found a gas not previously discovered on the earth, though it had been found in the luminous atmosphere of the sun, by means of the spectroscope in 1868, or about twenty-six years previously.

It may be noted that the name helium had been given to this ele- ment not helion, Nearly all the metals except the very common ones

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