Written for general readers by Niels Bohr’s close collaborator and a Danish physicist, with a foreword by Ernest Rutherford, this book explains how atoms became real, countable things. It moves from molecules, light waves and spectra through electrons and the nuclear atom to Bohr’s model of the hydrogen spectrum and its wider applications.
A clear contemporary snapshot of quantum physics just before wave mechanics, for readers curious about how the atom was understood. Download the free EPUB.