Books and Manuscripts

Chadwick, James
Autograph Letter, signed
Cambridge, March 30, 1932. Single sheet, 8 3/4 x 7 in. (222 x 178 mm). One-page autograph letter, signed by English physicist James Chadwick to George Frederick Kunz regarding his research on the Neutron: “Dear Mr Kunz, I am sorry that at the moment I can supply you with nothing of real interest about the neutron. It is possible, even probable, that I may be able to send you later photographs which show some of the effects of a neutron in passing through matter. Yours sincerely J. Chadwick.” On Chadwick's Bentley Road, Cambridge, personal stationery. Creasing from contemporary folds, very light dampstaining along right side; small stains from now removed paperclip, top verso edge. 

A fine letter from Nobel Prize-winning English physicist, James Chadwick (1891-1974), to noted mineralogist, mineral collector, and vice president of Tiffany & Co., George Frederick Kunz (1856-1932), penned during his momentous research and discovery of the neutron.

Only two months prior to writing this letter, Chadwick had begun his first experiments regarding the existence of a possible neutral particle in the nucleus of an atom, alongside electrons and protons, and with a mass slightly larger than a proton. In February 1932, after only two weeks of experiments, Chadwick published a paper, "The Possible Existence of a Neutron," where he suggested that the evidence favored the existence of the neutron as the interpretation of mysterious radiation, and which was previously identified as gamma ray photons by Frédéric and Irène Joliot-Curie. Less than two months following this letter, in May of 1932, Chadwick published a paper definitively titled "The Existence of a Neutron," announcing that the nucleus of the atom contained an uncharged particle, which he called the neutron. By 1934, the existence of the neutron was firmly established, and was a sea change for scientists views of the atom, allowing them to probe more deeply the composition of other nuclei. This had significant consequences when scientists used neutrons to hit uranium, causing a fission of the nucleus of uranium and creating a massive amount of energy, later utilized in the creation of the atomic bomb. For his discovery Chadwick was awarded the Nobel Prize in 1935. 

Letters from Chadwick during this important period are rare.