Famous First Words #2: Discovery of the Neutron - James Chadwick

Famous First Words is a recurring LabKitty feature in which we take a look at the opening line of an historic scientific article.

Ah the good ole days, when atoms were just protons, neutrons, and electrons, just like it said in your high-school science book. (Assuming you didn't go to high school in Texas. Rumor has it the TASB is changing the science books so that all occurrences of "atom" read "godicule.") These days, the standard model is a mishmash of eleventy whatever quarks and particles and force carriers; bosons and leptons and bears. Oh my.

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So is it we look back with fond nostalgia to James Chadwick's announcement that he had discovered the neutron. Rutherford's nucleus demanded the neutron exist (the whole schmeer was too light without it). The challenge at the time was detecting a particle that had no charge. How hard was it? Hard enough to get Chadwick a Nobel prize. And he did so with equipment not much more sophisticated than nerd kids would find under the Christmas tree before lawsuits became commonplace. Heutzutage, state-of-the-art equipment for particle physics doesn't even fit in a single country.

Here's how his announcement begins. (Sigh. You just don't see first-person-singular in journal articles anymore.)

Possible existence of a neutron
J. Chadwick Nature. 129:312 (1932)

I have made some experiments using the valve counter to examine the properties of this radiation excited in beryllium.