_Plato._ Cp. Timaeus, p. 46 A, 'Within the eyes they (the gods) planted that variety of fire which does not burn, but it is called light homogeneous with the light without. We are enabled to see in the daytime, because the light within our eyes pours out through the centre of them and commingles with the light without. The two being thus confounded together transmit movements from every object they touch through the eye inward to the soul, and thus bring about the sensation of the sight.' Grote's Plato iii. 265. _Archytas_ of Tarentum, a Pythagorean (circa 400 B.C.). _The Stoics_--believed that sight consisted in a refined fluid or visual effluence proceeding from the central intelligence through the eyes. 'In the process of seeing, the [Greek: horatikon pneuma] (visual effluence) coming into the eyes from the [Greek: hegemonikon] (central intelligence) gives a spherical form to the air before the eye by virtue of its [Greek: tonike kinesis] (i.e. the tension it sets up), and by means of the sphere of air comes in contact with things; and since by this process rays of light emanate from the eye, darkness must be visible.' Zeller, The Stoics, Epicureans, and Sceptics, p. 209, note. Cp. Plut. Plac. Phil. iv. 15. CHAPTER 16. _two rival images of the sun._ Apparently an allusion to the phenomenon of mock suns. Archimedes had, according to Apuleius, treated of the rainbow and the mock sun in connexion with his researches into mirrors. CHAPTER 17. _Marcus Antonius_, the orator, born 143 B.C., Consul 99 B.C. _Carbo_, consul 85-82 B.C., one of the leaders of the Marian party and the chief opponent of Sulla after Marius' death. _Manius Curius._ See note on chap. 10. _Marcus Cato_, consul in 195 B.C., conducted a successful campaign in Spain in that and the following year. CHAPTER 18. _Aristides_, the Athenian statesman and general, surnamed the just, died circa 468 B.C. _Phocion_, an Athenian general and statesman, born 402 B.C., died 317 B.C. He was famous for his virtue and his poverty. _Epaminondas_, the great Theban general who fell at Mantinea, 362 B.C. He was of noble birth but poor. _Fabricius._ See note on chap. 10. _Gnaeus Scipio._ Cp. Val. Max. iv. 4. 10. 'In the second Punic war Gnaeus Scipio wrote to the senate from Spain, begging that he might be replaced in his command. For his daughter was now of marriageable age, but could not be provided with a dowry during his absence from Rome.' _Publicola_ (_Valerius_), colleague of Brutus in the consulship in the first year of the Republic. _Agrippa_, Menenius, consul 503 B.C., mediator between the _plebs_ and the nobles in 493 B.C., in which year he died. _Atilius Regulus._ See note on _Serranus_, chap. 10. CHAPTER 20. _Philus_, a sceptical academician, one of the circle of Scipio Africanus the younger. _Laelius_, the intimate friend of the younger Africanus. _Crassus_, the famous financier, triumvir with Caesar and Pompey.