Periodic Table of the Elements on the front, together with Table of Chemical Elements on the reverse. An up-to-date listing as of 1947.
Stamps depict Niels Bohr, the equation for the Bohr frequency condition (an equation relating to light frequency and electrons), and a diagram of the Bohr model of a hydrogen atom.
Letter sent to the Secretary General of IUPAC in Paris during the Nazi occupation of World War II.
- Addressee Gerard, Jean
- Author Bohr, Niels, 1885-1962
- Contributor International Union of Pure and Applied Chemistry
- Subject Hahn, Otto, 1879-1968, Hevesy, Georg von, 1885-1966, Aston, Francis William, 1877-1945, Bohr, Niels, 1885-1962, International Union of Pure and Applied Chemistry, Nobel Prize winners