Original vintage semi-glossy 4 x 5.5 silver gelatin photograph of Niels Bohr and Ludwik Silberstein side-by-side, annotated on the reverse in Silberstein's hand, "December 5, 1923, Niels Bohr and L.S." Includes a hardcover first edition of Report on the Quantum Theory of Spectra by Dr. Silberstein, published in London by Adam Hilger, Ltd., 1920, 5.75 x 8.75, 42 pages; in the preface, Silberstein describes the thin volume as "a brief account of only the most important contributions to Quantum Theory of Spectra, a new field of inquiry opened only six or seven years ago by Niels Bohr." Silberstein notes the date of receipt from Hilger and lightly signs his initials, "L.S.," on the first free end page. In overall fine condition, with small mounting remnants to the reverse of the photo.
From the collection of physicist Ludwik Siberstein.
