Even Mendeleyev was perplexed at first. He even ventured to suggest the "saving" idea that argon was no new element at all. It was, he said, a sort of compound of nitrogen with three atoms in its molecule: N₃; like the ozone molecule O₃ which exists alongside the oxygen molecule O₂. But finally the facts convinced Mendeleyev of his error and he acknowledged Ramsay to be right. And now all the textbooks in the world name the English scientist as the discoverer of the group of noble gases, and nobody tries to challenge this fact.

   For twenty years N. Morozov, a member of the "Narodnaya Volya" group languished in the dungeons of the Schlusselburg Fort. Afterwards, under Soviet power, he became a world renowned scientist. The impenetrable walls of his stone prison were unable to break his will or to keep him away from scientific work. His persistent studies materialized in a number of daring and original ideas and hypotheses. In prison Morozov finished a study devoted to the Periodic System. In it he predicted the existence of elements which should be chemically inactive.

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