loco THEON. various writings to which his name is attached, in order. 1. Scholia on Aratns. Of these there are at least two sets, the second first printed by Buhle, in his edition, as cmendutiora. Grotius is of opinion that the first are not the work of Tlieon, but of several hands : this he infers from their containing repeti- tions and contradictions, which is not a very safe premise for the conclusion. Kuster (Suidas, s. v.) attributes them, without reason given, rather to Theon the sophist. That they are unworthy of the astronomer, is true enough ; but rejections made on such a ground are dangerous things. These scholia were printed in the Aldine* edition of Aratus, in that of Valder's collection [Ptole- MAEUS, p. 573], in Morell's edition, Paris, 1559, 4to., in Fell's, Oxford, 1672, 8vo, and also in Buhle's. H alma, in his edition (Gr. Fr.) Paris, 1 822, 4 to, has given selections, which his critics have asserted to be very ill chosen. (Hoffman, Leone. Bibliogr. vol. i. p. 233). 2. Edition of Euclid. Of the manner in which Theon is asserted to have edited Euclid we have already said enough. [Eucleides, pp. 68, b, Qd, b, 70, a.] 3. Ets t)]v rov TlToK^ixaiov ficyaKrjv aivra^iu virofjLUTjiiidToov Pi€ia la'. This is the great work of Theon, the commentary on the Almagest, addressed to his son Epiphanius. But the Almagest has thir- teen books, while Theon's commentary is marked as having only eleven. The commentary on the third book has not come down to us with the name of Theon, but with that of Nicolas Cabacillas ; and those on the tenth and eleventh books are joined together. The commentary on the later books is obviously mutilated by time ; for a circumstance connected with that on the fifth book, see Pappus. On this commentary, Delambre (who has given a full account of it, Hist Astron, Anc. vol. ii. pp. 550 — 616) passes the following judgment: " Theon commences by announcing that he will not follow the example of ordinary commentators, who show themselves very learned on passages which offer no difficulty, and are silent upon all which would give trouble to understand or to explain. He has not always kept this promise ; I have often referred for information, and I have only found Ptolemy's words faithfully copied or slightly modified. It is a paraphrase which may give some explanation of methods, but which really presents nothing which a little attention would not find in the text, none of those lost traditions, which must then have existed at the Observatory of Alexandria, nothing new upon the instruments or the method of using them. Theon seems to know no one but Ptolemy and to have read nothing but the Syntaxis This commentary is not what could have been made then, nor even what could have been made now." We have mentioned in the article Ptolemaeus all the editions of the commentary which accom- pany those of the text. The only separate edition (if it be right so to call it) is that of Halma, forming a continuation of the four volumes already mentioned in Ptolemaeus. tt includes only the • This Aldine edition, Venice, 1499, folio, is not a separate work, but part of what is frequently catalogued as Scriptores Astronomici Veteres, con- taining Julius Firmicus, Manilius, &c. as well as Aratus. THEON. commentary on the first and second books (Gr. Fr.) in two volumes, quarto, Paris, 1821 and 1822. 4. Commentary on the manual tables of Ptolemy, Knowledge of this work is very recent, and as it involves a work of Ptolemy himself which we have not mentioned in its place, a few words of expla- nation will be necessary. It was long known thju certain unpublished tables (as they were called) ol Theon existed in manuscript : and there is in Fabricius and others a frequent confusion of these tables with the chronological table presently men- tioned. Not but what accurate information might have been found. Kuster, speaking of an emend- ation of Suidas, who attributes to Theon a work ets rhp TiToKsjxaiov irpdx^tpov KavSpa, says that Theon wrote a commentary on the canOn of Ptolemy, which canon existed in manuscript in the Imperial library. Delambre found a manuscript in the Royal Library at Paris, which he has described (Hist. Astr. Anc. vol. ii. p. 616) under the head ©ewi/os 'AAe|ai/5p6ws Kcivoves irpSx^tpoi. Tables manuelles de Theon d* Alexandria This work was afterwards published by Halma, but under the title " Com- mentaire de Theon . . . sur les tables manuelles as- tronomiques de Ptolemee," in three parts, Paris, 1822, 1823, 1825, 4to. Having only very recently seen this last work, we have only as recently known that there is a distinct work of Ptolemy himself, the Kavovis Trpox^ipoi. Ptolemy's part is addressed to Syrus ; Theon's to his son Epi- phanius. The contents are, prolegomena, tables ot latitude and longitude, and a collection of astrono- mical tables, somewhat more extensive than those in the syntaxis. The prolegomena are separately headed ; one set is given to Ptolemy, another to Theon. But the tables themselves are headed TlToXefxaiov ©ecuvos, Koi 'TnaTias irp6x^ipoi. ltd- voves. Dodwell had previously printed a fragment of the prolegomena in his " Dissertationes Cy- prianae," Oxford, 1684, 8vo. 5. The continuation of the regal canon [Ptole- maeus, p. 572] down to his own time is attributed to Theon. In the manual tables it is carried down to the fall of the Eastern empire with the heading nToAe^atou, ®ec>)vos^ k. t. A. A very full dissertation on this canon is to be found in an anonymous work " Observationes in Theonis Fastos Graecos priores." Amsterdam 1735, quarto. The list of works attributed to Theon of Alex- andria by Suidas is MaflTj/xaTtKro, 'ApiOfxrjTiKa, Ufpl <Tr}iJ.ei(av kol (TKotttjs opveuy koX rrjs tcou KopoLKUP <po}vris, Tlep t^s toG Kwhs iiriroXris, Uepl tt^s roh Ne^Aou avagao-ewy, Els rhv UroXefxaiov irpox^ipov Kav6vay els rhv fiiKphv 'A(rTpod§ov vTro/JLvrj/jia. In the last, Fabricius proposes to read aarpo- A070V, taking the work to be a commentary on the collection of minor writers, which went by the name of the lesser Syntaxis. (Fa- bricius, Halma, Delambre, &c. opp. citt. edit, ciiat.) [A. DeM.] THEON (060)1'), literary. 1. A grammarian, who taught at Rome in the reigns of Augustus and Tiberius,.and was succeeded by Apion. ( Suid. s. v. ^ATTidv.) He was the author of a Lexicon to the Greek comedians (Kw/ij>cai Af|6is), which is quoted by Hesychms in the Prooemium to his Lexicon. (Also, s. V. SKlraKoi : see Ruhnken, Prae/. ad Hesych. pp. ix. foil.) It is doubtful whether he was the author of the comic lexicon quoted by the Scholiast to ApoUonius Rhodius (iv. pp. 280, 305), He is one of the authors from whose works the
