Word: hydrogens
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Dates: during 1930-1939
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...ultracentrifuge - a machine which separates heavy molecules from light ones, inferentially measuring their molecular weights, by whirling them at enormous speeds. In this ultracentrifuge the molecular weight of the Stanley crystals was found to be about 17,000,000 units (17,000,000 times as heavy as a hydrogen atom...
...virus, found to contain carbon, hydrogen, nitrogen and oxygen like thousands of organic compounds, could now be contemplated as a huge protein molecule -a "macro-molecule." Was it alive or not alive? No known living thing is crystalline in form. It would be fantastic to imagine a crystalline pig. Yet the virus showed the ability to reproduce itself in great quantities when stimulated by contact with a plant. Thus the Princeton chemist had discovered an apparent bridge between living and nonliving matter. This was a discovery of Nobel Prize calibre...
Lawrence regards this gift as one of his two luckiest '"breaks." The other was the fact that University of California's Gilbert Lewis was making heavy water, containing heavy hydrogen, soon after its discovery by Columbia's Urey. Lewis let Lawrence have generous samples and Lawrence was the first man to use the heavy hydrogen nuclei-deuterons-as atomic projectiles. They are more effective than protons, easier to handle than alpha particles...
...crew carry small electroscopes in their pockets which they discharge into a meter at the end of the working day to see how much radiation they have been exposed to. Since neutrons cannot be controlled by magnetic fields and slide easily through almost all substances except those rich in hydrogen, Dr. Lawrence moved the control panel 60 ft. away from the apparatus and surrounded the machine with tanks of water six feet high, three feet thick (every water molecule contains two neutron-braking hydrogen atoms). No one is allowed inside this barrier when the cyclotron is running. Experiments on rats...
...Only the hydrogen atom contains no neutrons...