Complete Extant Works of Hero of Alexandria, Vol. 3

kind, these are the more important examples: p. 174, 5 Vi. "to transfer to convenience, and the things falsely said"; p. 184, 3 "less"; p. 198, 19 "then let Δ be the dioptra, and BΓ the straight line. And of the descent, 2 cubits, and of the ascent, one cubit"; p. 198, 25 "in lines"; p. 200, 4 "parallel"; p. 208, 17 "thus ΓB toward BA. And let it have the ratio of ΓE toward AΔ"; p. 238, 5 "whenever we wish even while digging according to the vertical"; p. 246, 8 "and in it let there be two straight lines, KΛ and MN"; p. 254, 9 "let it be, etc., up to 'I wish'"; p. 262, 6 "neither to be contracted"; p. 276, 5 "to measure"; p. 300, 26 "each, up to 'and'."

The remaining Parisian codex among the Greek supplements no. 816 (cf. H. Omont, Inventory, vol. III, p. 313) is a transcript of the Parisian book no. 2430, made in the 19th century for the use of Vincentius.

In this shortage of critical aids, the booklet on geodaesia land surveying by an unknown Byzantine writer, edited by Vincentius1) Notices et extraits, vol. XIX, 2nd part (Paris 1858), p. 348 ff., provides assistance that should not be entirely disregarded. It is wrongly attributed to Hero of Byzantium against the authority of the archetype codex; for in the Vatican Greek codex no. 1605 (parchment, 11th century)—which K. K. Mueller (Rheinisches Museum, vol. XXXVIII [1883], pp. 454–463) taught to be the sole protection for editing this booklet—it is handed down without a title. The author of this work, just as he seems to have collected almost all the material of his discussion from older writers, so he himself declared in explicit words that he used Hero’s book on the dioptra (p. 388). Since he used a codex here and there better than the old Parisian one available to us, it provides utility for removing certain errors, especially in chapter XXXI. But the description of the dioptric instrument, which seems to have once been placed between the first and second chapters of geodaesia, perished when some quaternions of that archetype codex were lost; if it existed, it would contribute something to filling that gap in Hero’s booklet.