“Si litteras parabolico speculo inscripseris idque tempori plenilunii Lunae exposueris eae litterae ceu in vasto quodam speculo impressae reflexaeque ubilibet locorum legi poterunt. Ita Pythagoram aiunt, dum Hydrunti moraretur, litteras Lunae inscriptas Constantinopoli amicis legendas dedisse.”
There is also a passage in Dr. Thomas Browne’s Pseudodoxia Epidemica (Vulgar Errours), p. 60 (Edition of 1650), in reference to this myth: “Which is a way of intelligence very strange; and would requite the Art of Pythagoras; who could read a reverse in the Moon.”
Other references in occult literature to the alleged mirror of Pythagoras are as follows:
Athanasius Kircher. Ars Magna Lucis et Umbrae (Cryptologia, cap. i.) (Romae, 1646, fol.), p. 908. (Quotes from Cornelius Agrippa and Porta, and denounces the account as absurd, and against natural possibility.)
Bubalus. Commentationem de Angelis (Lugduni, 1622, fol.), 9-50, art. 1, quaesito 2, difficult. 2, § 3, pp. 64-66. (Combats views of Paracelsus.)
Paracelsus. Magia, lib. 5, de Speculi constitutione. (Distinguishes five kinds of alleged magic mirrors; none of them, however, having any optical significance.)
Boissardus. Tractatus de Divinatione (Oppenheim, 1616, folio), p. 297.
(ii.) Aulus Gellius. Carus Sterne (Gartenlaube, 1877) and Ayrton (Journal Royal Institution, 1879) refer to Aulus Gellius as having written of mirrors which “sometimes reflected their backs and sometimes did not.” The reference appears to be a mistaken one; for all I have been able to find in Aulus Gellius is the following passage in the Noctes Atticæ, bk. xvi., ch. xviii. (which is upon that branch of Geometry called ὀπτικὴ):
Ὀπτικὴ facit multa demiranda id genus; (1) ut in speculo uno imagines unius rei plures appareant; (2) item, ut speculum, in loco certo positum, nihil imaginet, aliorsum translatum, faciat imagines; (3) item, si rectus speculum spectes, imago fiat tua hujusmodi, ut caput deorsum videatur pedes sursum.
The passage which I have put into italics appears to have been mistaken in meaning. In Beloe’s translation, vol. iii., p. 249, this clause is rendered as follows: “A glass placed in a certain position shows nothing. Turn it, and it shows many things.” This is hardly adequate. More accurately it should run: “A mirror set in a certain place shows no image, but when transferred to another position produces images.” There is nothing in this at all suggestive of the mirror reflecting from its face the pattern on its back.
(iii.) Muratori. Sterne (op. cit.) and Ayrton (op. cit.) refer vaguely to the Italian historian Muratori as the authority for accounts of a “magic mirror found under the pillow of the Bishop of Verona, who was afterwards condemned to death by Martin (sic) della Scala, as well as of the one discovered in the house of Colla da Rienzi (sic) on the back of which was the word ‘Fiorone.’” The bishop in question was Bartolomeo dalla Scala, who was put to death in 1338 by Mastino della Scala, as narrated by Muratori (Annali d’Italia, vol. viii., p. 212, of the folio edition of 1744-49). Cola di Rienzo (or Rienzi) is mentioned many times in the same volume viii. I have not, however, been able to find in this work the mention of the mirror in either case. Neither have I found any as yet in Lessmann’s life of Mastino della Scala (Berlin, 1829); nor in Du Cerceau’s Life and Times of Rienzi (Lond. 1836). Muratori was, however, a prolific writer. Amongst his works were: Delle forze dell’ Intendimento Umano; Riflessioni sopra il Buon Gusto nelle Scienze e nelle Arte; La Filosofia Morale. It is possible that the reference may be to some passage in these. Muratori also refers to a Vita di Cola di Rienzo, the authorship of which is unknown to me.
(iv.) Von Humboldt. In 1830 Von Humboldt brought a supposed magic mirror from Berlin to Paris to exhibit it to members of the Académie des Sciences. It was indeed shown to some of them at the apartments of M. Arago at the Observatoire. No reference to the occurrence is to be found in the journals of the Académie, published or private, or in any contemporary journal. Perhaps the reason is that, as is known, the experiments proved a total failure. My information on the subject is derived from Bertin (Ann. Chim. Phys., xxii., 1881, p. 478).
(v.) Babinet. The name of Babinet is sometimes given along with that of Arago in connection with this subject; but I am unable to find that he did anything.