particulars from those of Hero: he does not even notice the application of the forcing-pump in extinguishing conflagrations. This silence on the part of Vitruvius and Pliny, so remarkable on the supposition that Hero was an original discoverer, is more easily accounted for if we regard him rather as the interpreter of Ctesibius.[4] For further details on the life and writings of Hero, the reader is referred to Fabricius, iv. pp. 222–239, Smith’s Dictionary of Biography, and Baldi _de Vita Heronis_, in his edition of the Belopœica. J. G. G. Jan. 31, 1851. FOOTNOTES: [1] This has, indeed, been conjectured to be an error for Ἥρωνος ἢ Κτησιβίου, but Baldi (in his edition of the Belopœica, p. 44,) has satisfactorily proved that Hero was the writer. [2] That Ctesibius began his researches at an early age may be inferred from the fact mentioned by Vitruvius, ix. 9. (edit. Schneider.) [3] On Vitruvius, x. 7. The sections of Hero and the corresponding chapters of Vitruvius are minutely compared by Schneider, Vitruv. vol. iii. pp. 283–330. [4] Baldi arrives at the same conclusion: (p. 74) “Cæterum haud immerito quispiam dubitaverit quam ob rem Architectus Heronis nostri nomen silentio præterierit. Nos ideo factum putamus quod ille Ctesibio utpote inventori ea tribuere maluerit quæ ab Herone locupletiora et illustriora quam ipse a magistro accepisset evulgata fuere.” CORRIGENDA. Page 4, line 3, _for_ them _read_ it. 14, figure. The mouth of the vessel should be open. 25, line 8, _for_ ⁷⁄₀₁ _read_ ⁷⁄₁₀. 35, .. 25, after P R, _read_ so that the goblet may be filled, and the pedestal M N O X as high, &c. 40, .. 6, for _Wine and Water_ read _Wine-and-Water_. —, figure. The pipe S T should connect the vessels A B and C D near their bases. 43, line 23, _for_ across a third pulley, C, to another pulley, S, _read_ across the pulley S to another pulley, T. 61, .. 12, _dele_ , _after_ vessel. 62, .. 7 } —, .. 27 } _for_ the Hercules _read_ Hercules. 63, .. 6 } 79, .. 1, _dele_ , after _attached_. 84, .. 4, _read_ (from which extends the hand of the figure which is to pour the libation.) —, .. 6, _read_ side of the wine vessel. 89, .. 23, _for_ escaping _read_ entering. 96, .. 18, _dele_ , _after_ partition. 105, .. 6, _after_ this _insert_ and communicating with it. [Illustration: Decorative border of curled leafy vines.] CONTENTS. Page 1. The bent Siphon 11 2. Concentric or inclosed Siphon 14 3. Uniform discharge Siphon 16