a. Obs. [Fancifully f. Gr. Τῑθων-ός, spouse of Eos (Aurora) + -IC.] Pertaining to or characterized by ‘tithonism’; = ACTINIC. Hence † Tithonicity Obs. = ACTINISM 2.
1842. (Dec.) Draper, in Philos. Mag., XXI. 455. Such words as Tithonoscope, Tithonometer, Tithonography, Tithonic effect, Diatithonescence, are musical in an English ear. In this paper I shall therefore use the term Tithonicity and its derivatives. Ibid. The proof of the physical independence of Tithonicity and Light. Ibid. The existence of dark Tithonic rays, analogous to the rays of dark heat. Ibid., 457. To insulate a visible red and yellow ray that are without tithonic power, and an invisible tithonic ray beyond the violet.
1854. J. Scoffern, in Orr’s Circ. Sc., Chem., 93. The immediate mode of agency of the power—‘actinism,’ ‘tithonicity,’ ‘energia,’ or whatever we may call it—is … unknown.
1882. Nature, XXV. 274. The works … from Draper’s pen upon the chemical and physical properties of the ultraviolet, or as he styled them, tithonic rays.
