London: Royal Society, 1933. 1st Edition. FIRST EDITION IN ORIGINAL PAPER WRAPS OF THE FIRST CONFIRMATION OF THE IDENTIFICATION OF POSITIVE ELECTRONS, THE FIRST PUBLISHED PHOTOGRAPHS OF POSITIVE ELECTRONS, & THE FIRST DETAILED DESCRIPTION OF THE DESIGN OF THE COUNTER CONTROLLED CLOUD CHAMBER WHICH MADE THIS SCIENCE POSSIBLE. The wraps are housed in a custom clamshell case.
Blackett and Occhianlini’s famous paper is also the first to mention the connection between the discovery of the positive electron and Dirac's prediction of an anti-electron, hence it is also the first indication of positive and negative electron pair production. The paper is inclusive of photographic plates (15 photographs in total). In 1948 Blackett won the Nobel Prize "for his development of the Wilson cloud chamber method, and his discoveries therewith in the fields of nuclear physics and cosmic radiation" (Nobel Prize Committee).
In 1928 Dirac proposed the famous Dirac equations – equations that “worked as well with negative energy quantum states (antiparticles) as with positive energy quantum states (particles)” (History of Physics: The Wenner Collection). By 1931, Dirac had concluded that “the negative energy quantum state must be an ‘anti-electron’ with the same mass as an electron. And while this particle would not be found in nature because of its destructive interaction with electrons, Dirac predicted that it could be observed if produced experimentally.
“In 1932, Anderson discovered the anti-electron (which he called ‘positive electron’) by allowing high energy cosmic rays to pass through a cloud chamber and a lead plate. In [March, 1933 paper], Blackett and Occhialini confirmed Anderson’s sightings of positive electrons in a paper [this paper] that also proposed the mechanism of antiparticle creation and annihilation” (Wenner). In this same paper, the two are also “the first to report a phenomenon they called a cosmic-ray shower, an avalanche of reactions in which more and more charged particles are produced” (Brandt, Harvest of the Century, 216).
In summary, Blackett and Occhialini’s paper presents (1) A detailed description of a method of making particles of high energy take their own cloud photographs, the counter controlled cloud chamber. (2) The most striking features of some 500 photographs taken by this method are described, and the nature of the showers of particles producing the complex tracks is discussed. (3) A consideration of the range, ionization, curvature and direction of the particles leads to a confirmation of the view put forward by Anderson that particles must exist with a positive charge but with a mass comparable with that of an electron rather with that of a proton. (4) The frequency of occurrence of the showers is discussed, and also their possible relation to the bursts of ionization.
Still, Blackett and Occhialini were cautious; they ended their paper stating: ’When the behavior of the positive electrons have been investigated in more detail, it will be possible to test these predictions of Dirac’s theory. There appears to be no evidence as yet against its validity, and in its favour is the fact that it predicts a time of life for the positive electron that is long enough for it to be observed in the cloud chamber but short enough to explain why it had not been discovered by other methods’ (Blackett 1933a, 714-716). Item #980
CONDITION & DETAILS: London: The Royal Society. Complete issue housed in custom case gilt-lettered at the spine. 4to 10 x 6.75 inches (250 x 169mm). Continuously paginated, pp. 475-727. Blackett paper: 4 photographic plates. The issue is in fine condition with a light stamp of the University College of Wales at the top of the front wrap (see photos). The wraps are clean, bright, and solid; the interior as well.