Archive of historical materials
Envelope: Interaction of El. Particles I, 1934
OU1934-A1 (2 pages) Date: 1934
Yukawa’s meticulous organization of research materials began with this brown envelope.
In his second year at Osaka Imperial University, Yukawa was working day in and day out to find out what kind of force holds the protons and neutrons together in the atomic nucleus. On October 9, 1934, he formulated an idea of gamma-prime ray (γ’ ray) (now called a pi meson). This brown envelope contained a valuable lecture manuscript and draft of paper.
“Interaction of El. Particles. I, 1934” was handwritten by Yukawa on the front of the envelope. The casually written English harmonizes beautifully with the brown envelope. “Osaka Imperial University” is also printed in English on the front of the envelope. On the back of the enveloped, “Osaka Imperial University, Department of Science, Faculty of Physics” is printed in Japanese. (Written by Yutaka Hosotani)
