There had been attempts before Mendeleyev's to put the sixty-odd chemical elements then known into some kind of order. But they were not successful. The Englishman Newlands probably came the closest to the truth. He suggested a "Law of Octaves." On arranging the elements in order of increasing atomic weight Newlands found that as in music where each eighth note repeats the first at a higher level, the properties of every eighth element resembled those of the first. But the reaction Newlands' discovery evoked was: "Why don't you try arranging the elements in alphabetical order? You might detect some regularity that way too!"

   What could poor Newlands reply to his sarcastic opponent? Mendeleyev's Table was not particularly lucky at first. Its "architecture" came under furious attack. For much in it remained obscure and required explanation. It was easier to discover half-a-dozen new elements than to find proper positions for them in the table.

   Only on the first floor did things seem satisfactory. There was no danger of an unexpected flow of lodgers here. This floor is inhabited now by hydrogen and helium. The nuclear charge of the hydrogen atom is +1, and that of the helium atom +2. There clearly are not and cannot be any other elements between them. There are no nuclei or other particles in nature that we know of, whose charges are fractional numbers.

   (Recently, however, theoretical physicists have persistently been discussing the question of the existence of quarks. This is the name given to primary elementary particles from which all the rest can be built, including protons and neutrons, the component parts of atomic nuclei. Quarks are assumed to have fractional electric charges: +1/3 and –1/3. If quarks actually exist, the "material arrangement" of the universe may appear in a new light.)

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