Perhaps a good place to begin the history of nuclear physics would be with the famous story of an accidental discovery by Henri Becquerel in the late 1800s. He had experimented with a photographic plate sprinkled with a layer of uranium salt and exposed to the sun. He had seen the silhouette of the phosphorescent substance in black on the negative. “When he tried to repeat his experiment…Paris was (overcast) gray. He put the covered photographic plate away in a dark drawer, uranium salt in place.” He decided to develop the plate despite the fact it hadn’t been exposed to the sun as planned and found that “the silhouettes appeared with great intensity.” He had discovered energetic, penetrating radiation, which, in turn, inspired Rutherford and the Curies in their research. Marie Curie named the phenomenon radioactivity. The field of the investigation grew and Frederick Soddy, working with Rutherford, observed spontaneous disintegration of radioactive elements. The yet-unnamed field of nuclear physics began to reveal mysteries to those who struggled to study and understand.
The observation of “spontaneous disintegration of radioactive elements” leads me back to The World Set Free by Wells. That book introduces the first references I’ve been able to find on the application of nuclear energy in the form of an atomic bomb. The revelations begin with a fictional young man named Holsten listening to a professor’s lecture on radium and “radio-activity” and describing how radium was “breaking up and flying to pieces.” The professor mentions uranium and thorium and explains that “the atom…is really a reservoir of immense energy.” He goes on to describe how in fourteen ounces of the element uranium “slumbers a least as much energy as we could get by burning a hundred and sixty tons of coal.” He then mentions that a sudden release of the energy “would blow us and everything around us to fragments…(or) keep Edinburgh brightly lit for a week.” He then proposes using this energy to drive giant battleships or (ocean) liners and predicts that “man’s material destiny” will be changed forever. Inspired by what he heard in 1933, Holsten begins to introduce atomic energy to propel, “automobiles, aeroplanes, water planes and such-like mobile purposes.” France alone had thirty thousand “atomic aeroplanes by 1943. Gold was produced as a waste product of the disintegration of heavier elements and was “undergoing headlong depreciation.”