Word: weighting
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Dates: during 1910-1919
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...University wrestling team is still in need of more material. A heavy-weight for the regular team has not yet been selected, and good men will be able to win a place in some of the other weights. Candidates should report at the Hemenway Gymnasium any afternoon except Saturday at 5 o'clock...
...purpose of really determining whether lead from radioactive sources actually had an atomic weight as low as 206, that Professor Richards and Dr. Lambert undertook their experiment. The most notable thing in connection with the investigation, aside from the astonishing results secured, as the hearty co-operation of the chemists of other countries, prominent investigators of England, Germany, Norway, Russia, and Austria all contributing samples of lead from radioactive sources, for investigation...
...complicated. The experiments were carried out with the greatest thoroughness, especial care being taken to have the materials as pure as possible. The results of the investigation were amazing. It was found that all of the radioactive speciments, obtained from uraninite, carnotite and thorianite, exhibited a lower atomic weight than ordinary lead, as determined under identical conditions, the deficiency in one case amounting to as much as 0.75 of a unit...
...simple linear quantitative relationship between the exact amount of radioactivity and the atomic weight was found. The ultra-violet spectrum of a typical specimen appeared to be exactly identical with that of ordinary lead. The necessary inference seems to be that lead from radioactive sources consists of a mixture of at least two substances, of which one is ordinary lead. The foreign substance must be very similar to ordinary lead and very difficult if not impossible to eliminate by chemical means; for many precautions were taken to purify the samples. This substance cannot be identified in the ultra-violet spectrum...
This amazing outcome is contrary to the customary experience with several other elements, notably copper, silver, iron, sodium, and chlorine, each of which seems to give a constant atomic weight, no matter what the geographical source may have been. No attempt is made here to discuss the theoretical aspects of the facts presented, but attention is called to their qualitative agreement with the hypothesis brought forward by Dr. Fajans and by Dr. Soddy, that some of the places in the periodic table, corresponding to high atomic weight should perhaps include several elements, different in atomic weights, but very similar...