1900 Daily Express 31 July 2/6 Plasmon is nothing more or less than milk dried after removing the cream and sugar.

1901 Daily Tel. 18 Mar. 11/6 (advt.) Plasmon is the albumen of pure fresh milk in the form of a dry, soluble, granulated white powder.

1909 Geogr. Jrnl. 40 259 We carried several tins of plasmon with us for use on an ascent of the Jonsong peak.

1921 R. Whymper Cocoa & Chocolate (ed. 2) xxiv. 360 Plasmon, which was regarded as a soluble form of milk proteid, is rendered to some extent insoluble when added to cocoa.

1985 R. Huntford Shackleton x. 95 They were eating Plasmon, a product made of concentrated casein.

1932 Proc. 6th Internat. Congr. Genetics II. 281 The abnormal development of chlorophyll (pale color) may be caused by a non-Mendelian nuclear or cytoplasmic factor or by a certain state of the genome or plasmon.

1954 P. Michaelis in Adv. Genetics VI. 290 I propose..with Renner (1929) to include all extranuclear hereditary elements of the cell in the term plasmon, and to subdivide this into (1) the cytoplasmon, that is, the elements of the cytoplasm, and (2) the plastom, that is, the hereditary elements of the plastids, [etc.].

1970 T. Dobzhansky Genetics Evol. Process x. 345 The plasmon of E[pilobium] luteum has retained its properties despite having carried an E. hirsutum genome for several generations.

1976 P. Bell & D. Coombe tr. Strasburger's Textbk. Bot. (new ed.) 401 Plastome and plasmone mutations have been insufficiently studied..but their importance for evolution should not be underestimated.

1986 Theoret. & Appl. Genetics 73 175/1 The mitochondrial and chloroplast genome differentiation most certainly accounts for the plasmon variability known in this genus.

1955 W. Bostick Anat. of Plasmons (U.S. Atomic Energy Comm., Rep. UCRL-4530) 2 Plasmons (plasma-magnetic entities) are toroidal packages of plasma wrapped up in their own magnetic fields.

1963 Soviet Astron. 6 471/2 If the ‘plasmons’ ejected by the ‘active’ nuclei of radio galaxies experience no deceleration, the age of sources similar to Centaurus A and Fornax A will not exceed 10⁸ years.

1971 R. C. Haymes Introd. Space Sci. xv. 447 The jet [of the galaxy M87] appears to be composed of a group of irregular concentrations of plasma, called ‘plasmons’ by some.

1974 Nature 23 Aug. 629/2 Christiansen has shown that a plasmon can travel a distance D = M/(π × 1·67 × 10⁻²⁴n_s r²) before dispersing. Here M is the mass of the plasmon, r its radius and n_s the number density of the gas surrounding the component.

1956 D. Pines in Rev. Mod. Physics 28 184/1 The valence electrons in the solid..are capable of carrying out collective oscillations at a high frequency... The valence electron collective oscillations resemble closely the electronic plasma oscillations observed in gaseous discharges. We introduce the name ‘plasmons’ to describe the quantum of elementary excitation associated with this high-frequency collective motion.

1966 C. Kittel Introd. Solid State Physics (ed. 3) viii. 233 It is possible to excite a plasmon by passing an electron through a thin metallic film..or by reflecting an electron from the film.

1983 Science 8 July 118/2 The plasmon resonance frequency is determined by the shape and dielectric properties of the metal particle.

1992 S. P. Maran Astron. & Astrophysics Encycl. 486/2 In a hot plasma, thermal fluctuations in the electron charge density (called plasmons) can create neutrino–antineutrino pairs via an interesting quantum mechanical process.