Sixteen years later all three of these
predicted elements had been discovered, one by a Frenchman, one by a
German and one by a Scandinavian, and named from patriotic impulse,
gallium, germanium and scandium. This was a triumph of scientific
prescience as striking as the mathematical proof of the existence of the
planet Neptune by Leverrier before it had been found by the telescope.
But although Mendeleef's law told "the truth," it gradually became
evident that it did not tell "the whole truth and nothing but the
truth," as the lawyers put it. As usually happens in the history of
science the hypothesis was found not to explain things so simply and
completely as was at first assumed. The anomalies in the arrangement did
not disappear on closer study, but stuck out more conspicuously. Though
Mendeleef had pointed out three missing links, he had failed to make
provision for a whole group of elements since discovered, the inert
gases of the helium-argon group. As we now know, the scheme was built
upon the false assumptions that the elements are immutable and that
their atomic weights are invariable.
Pages:
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433