"Two parallel straight lines never intersect," asserted geometry through the lips of Euclid, the greatest mathematician of antiquity.

   "Not so, they must intersect! declared the Russian scientist Nikolai Lobachevsky in the middle of the last century. And thus was born a new geometry, known as non-Euclidean geometry. "Moonshine and gibberish!" was what many leading scientists said about it at first. But were it not for non-Euclidean geometry we would have neither the theory of relativity nor the daring ideas of the laws governing the structure of the universe.

   Many of you have no doubt read A. Tolstoy's "Engineer Garin's Hyperboloid." "Excellent science fiction, " was the verdict of literary critics the world over. "Fiction that can never become reality!" echoed the scientists. Tolstoy died only fifteen years before the first ruby crystal emitted a light ray of unheard of brightness and power, and the word "laser" became known to by no means only specialists.

   Enthusiast-chemists continued to believe stubbornly in the possibility of conquering the unheard of obstinacy of the inert gases. If we took the trouble to thumb through the yellowing pages of scientific journals of the twenties, thirties and forties, we should come across quite a few curious articles and notes which show that chemists never relinquished the hope of drawing the inert gases into the sphere of their activities.

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