[Footnote 194: Plutarch ap. Eusebium Præp. Evang. i. 8; Aristotel. De Animâ, i. 2; Diogen. Laert. ix. 53. [Greek: Dioge/nês kissêroeidê= ta\ a)/stra, diapnoi/as de\ au)ta\ nomi/zei tou= ko/smou, ei)=nai de\ dia/pura; sumperiphe/resthai de\ toi=s phaneroi=s a)/strois a)phanei=s li/thous kai\ par' au)to\ tou=t' a)nônu/mous; pi/ptonta de\ polla/kis e)pi\ tê=s gê=s sbe/nnusthai; katha/per to\n e)n Ai)go\s potamoi=s purôdô=s katenechthe/nta _a)ste/ra_ pe/trinon.] This remarkable anticipation of modern astronomy--the recognition of aerolithes as a class of non-luminous earthy bodies revolving round the sun, but occasionally coming within the sphere of the earth's attraction, becoming luminous in our atmosphere, falling on the earth, and there being extinguished--is noticed by Alex. von Humboldt in his Kosmos, vol. i. p. 98-104, Eng. trans. He says--"The opinion of Diogenes of Apollonia entirely accords with that of the present day," p. 110. The charm and value of that interesting book is greatly enhanced by his frequent reference to the ancient points of view on astronomical subjects.] [Footnote 195: Plutarch, Placit. Philos. ii. 8; Panzerbieter ad Diog. Ap. c. 76-78; Schaubach ad Anaxagor. Fr. p. 175.] [Footnote 196: Plut. Ap. Euseb. Præp. Evang. i. 8.] [Footnote 197: Preller, Hist. Philosoph. Græc.-Rom. ex Font. Loc. Contexta, sect. 68. Preller thinks that Diogenes employed his chief attention "in animantium naturâ ex aeris principio repetendâ"; and that he was less full "in cognitione [Greek: tô=n meteô/rôn]". But the fragments scarcely justify this.] [Side-note: Leukippus and Demokritus--Atomic theory.] Nearly contemporary with Anaxagoras and Empedokles, two other enquirers propounded a new physical theory very different from those already noticed--usually known under the name of the atomic theory. This Atomic theory, though originating with the Eleate Leukippus, obtained celebrity chiefly from his pupil Demokritus of Abdera, its expositor and improver. Demokritus (born seemingly in B.C. 460, and reported to have reached extreme old age) was nine years younger than Sokrates, thirty-three years older than Plato, and forty years younger than Anaxagoras.[198] The age of Leukippus is not known, but he can hardly have been much younger than Anaxagoras. [Footnote 198: Diogen. Laert. ix. 41. See the chronology of Demokritus discussed in Mullach, Frag. Dem. p. 12-25; and in Zeller, Phil. der Griech., vol. i. p. 576-681, 2nd edit. The statement of Apollodorus as to the date of his birth, appears more trustworthy than the earlier date assigned by Thrasyllus (B.C. 470). Demokritus declared himself to be forty years younger than Anaxagoras.] [Side-note: Long life, varied travels, and numerous compositions of Demokritus.]