Translator's Preface

CONCERNING Hero of Alexaudria, the author of the treatise here translated, little is known with certainty. When his name and the place of his abode have been given, all that can be positively affirmed is exhausted. We are further told by hero the younger, who is supposed to have written in the seventh century A.D., that Hero, the author of the Pneumatics,"was a pupil of Ctesibius ; -a statement sufficiently probable from the character of his works, and strengthened by the inscription {GREEK}* prefixed to another work by Hero on the construction of missiles.

* This has, indeed, been conjectured to be an error for {GREEK} but Baldi (in his edition of the Belopoeica, p. 44,) has satisfactorily proved that Hero was the writer.

Even the precise period at which Hero lived is a debated point. From his own writings all that can be gathered is that he knew the works of Archimedes, and of Philo the Byzantian, who, again, is known to have been a contemporary of Ctesibius ; and, as the earliest mention of him by others is as low down as the fourth century A.D., external evidence, even if it were distinct, would be little trustworthy. Such evidence, however, is vague and scanty. The only direct statement bearing on the date of Hero is the assertion that he was pupil of Ctesibius. The date of Hero therefore depends on the date of Ctesibius, and this has been variously fixed by different chronologists.

Clinton, (F. H. vol. iii. pp. 535, 538,) who puts Hero as low down as the end of the second century B.C., proceeds on the following evidence : Athenaeus (vol. iv. p. 174, edit. Schweighaeuser) quotes one Aristocles as saying, in a work {GREEK}, of the water-organ, {GREEK}. Now Euergetes II (Ptolemy VII.) reigned from B.C. 170 to B.C. 117, and hence Clinton assigns Hero, the pupil of Ctesibius, to the reign of Ptolemy VIII. that is, to B. C. 117-81.

Fabricius, on the other hand, (Bibl. Graec. vol. iv. pp. 222, 234, edit. Harl.) setting out from an entirely different datum, places him more than a hundred years earlier, in the time of Ptolemy Philadelphus (Euergetes I.): Athenaeus Mechanicus, (one of the mechanical writers whose works are printed in the Veterum Mathematicorum Opera), in his treatise {GREEK}, p.8, speaks of Ctesibius as a contemporary; his words are {GREEK}. This treatise is dedicated to a Marcellus, and Fabricius, assuming, after Hero junior, this Marcellus to be the conqueror of Syracuse, has hence assigned Ctesibius and Hero to the reigns of the second and third Ptolemies (B. C. 285-222).

Of these conflicting dates that assigned by Clinton has been generally adopted. The question is discussed at some length by Schweighaeuser, in a note on the passage of Athenaeus referred to above: he deems the identification of the patron of Athenaeus Mechanicus with the conqueror of Syracuse to be unwarranted, and, besides, thinks it most unlikely that at so early a period a Greek should dedicate a work on military engines to any Roman. But from the expression employed by Athenaeus, {GREEK} it may be inferred that his patron was a man of very exalted rank; and the second objection from the alleged improbability that a Greek should dedicate such a work to a Roman at that period will hardly be thought to apply at the period referred to, while the skill displayed by Marcellus in the siege of Syracuse, and the regret expressed by him for the fate of Archimedes, (whether genuine or not,) may well have suggested the dedication to him of a work on military engineering. The assumption of Fabricius; then, is, in itself, not to be too hastily rejected ; and it will be seen that it is not so irreconcileable with the statement of Aristocles as has been supposed. Fabricius has carried back the date further than his argument requires or even warrants. Marcellus was killed B.C. 208: Athenaeus might have inscribed his work to him about B. C. 212 or 210; at this period, then, we must suppose Ctesibius to have been known as a philosopher,* but he may have lived far into the succeeding century,-possibly even into the reign of Euergetes II. (B. C. 170-117); Hero would thus be placed about B. C. 150, a result by no means inconsistent with the statement of Aristocles, since it is not necessary, with Clinton, to assign the whole of the long reign of Euergetes II. to Ctesibius, and then to put Hero so low down as the reign of Ptolemy VIII.

* That Ctesibitis began his researches at an early age may be inferred from the fact mentioned by Vitruvius, ix. 9. (edit. Schneider.)

The treatise on Pneumatics was frst published in an Italian translation by Aleotti (Bologna, 1547). In 1575 appeared a Latin version by F. Commandine (Urbino, 1575): this translation, through which the work has been most extensively known, was reprinted at Amsterdam and at Paris. Several other translations were made into Italian, and one into German (see Fabricius, iv. p.235). It was not till the year 1693, and subsequently to the appearance of 41 the versions named above, that the Greek text was published at Paris in the Veterum Mathematicorum Opera. The design of this collection was formed by Thevenot, deputy librarian of the Royal library in the reign of Louis XIV., and after his death it was carried out by De la Hire. Thevenot's plan was to publish an accurate transcript of the MSS. of the several authors. The inevitable obscurity arising from the numerous corruptions which had crept into the manuscripts was to be remedied by an appendix of notes and a Latin translation. But for the Pneumatics of Hero it seemed sufficient to adopt the already well-known translation of Commandine; and, in consequence, of the eight MSS. of this treatise existing in the Royal Library, that one was chosen which most nearly agreed with the Latin version. This MS. was closely followed, and, as might be expected, the printed text is extremely corrupt: not unfrequently entire clauses are wanting, which, ending with the same word as the clause preceding, seem to have been passed over by the transcriber, whose eye, in returning from his copy to the original, rested on the second instead of the first of the two similar words. These defective passages, which appear to have been conjecturally restored by Commandine, have been supplied in the present transllation from MSS. of Hero preserved in the British Museum. These MSS. are described in the appendix, where the most important cases in which the printed text has been supplemented, or otherwise amended, from this source are collected. When any words are included in the translation between brackets, it is to be understood that they appear neither in the text nor in any of the MSS. collated, but have been inserted as necessary to the sense.

The other treatises of Hero are : -1. On the construction of slings. 2. On the construction of missles. 3. On automata. These are published in Greek and Latin in the Vet. Math. 4. On the method of lifting heavy bodies. This treatise has not yet been edited : it exists only in an Arabic translation. 5. On the " dioptra" or spying-tube : also inedited. It exists in manuscript in the Royal Library at Vienna, and among the MSS. of Hero contained in the Library of the University of Strasburgh. Schweighaeuser in his notice of these MSS. (ap. Fabric. iv. p.226), intimates that this treatise is of much interest, and contains an account of the dioptra " newly invented or improved by Hero himself." Some help might perhaps be derived from it towards the settlement of Hero's date, as the dioptra is mentioned and minutely commented on by Polybius. Several other treatises, entirely lost, are enumerated by Fabricius, iv. p.236.

A question of great interest presents itself as to the claim of Hero to be considered as the inventor of the several machines and methods described by him. In the introduction of the "Pneumatica" he declares that his purpose is to arrange in order the discoveries of his predecessors, and to add to them his own. The treatise on the construction of missiles is ascribed in some MSS. to Ctesibius, (as in one at Leyden, Fabric. iv. p.229,) while at the end of a MS. of the same work in the Library of Vienna are these words, {GREEK}. Again, it is singular that neither Pliny nor Vitruvius has any reference to Hero, though Ctesibius and his inventions are repeatedly mentioned. Vitruvius (x. 7) minutely describes a machine for raising water to a great height, which he expressly ascribes to Ctesibius; and in the following chapter he treats, at great length, of the construction of water-organs, yet without any notice of Hero. Both Pliny and Vitruvius expressly name Ctesibius as famous for his skill in the invention of pneumatic and hydraulic instruments. Pliny's words are (vii. 38) "Laudatus est Ctesibius pneumatica ratione et hydraulicis organis repertis." Vitruvius, (x. 7, compare also ix. 8,) after his description of the machine for raising water, says "Nec tamen haec sola ratio Ctesibii fertur exquisita, sed etiam plures et varus generibus ab eo liquore pressionibus coacto spiritus efferre ab natura mutuatos effectus ostenduntur, uti merularum aquae motu voces, atque engibata, quae bibentia tandem movent sigilla, caeteraque quae delectationibus oculorum et annum usu sensus eblandiuntur." He refers the curious to the commentaries of Ctesibius himself. How well this description of Ctesibius' inventions suits the general character of those preserved by Hero, will be manifest at once. Vitruvius as Schneider has pointed out,* seems to have had no knowledge of Hero's Pneumatics, as both the forcing-pump and the water-oroan differ in several important 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.+ 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 edihon of the Belopoeica.

J. G. G.

Jan. 31, 1851

* On Vitruvius, x. 7. The sections of ilero and the corresponding chapters of Vitruvius are minutely compared by Schneider, Vitruv. Vol. iii. pp. 283-330.
+ Baldi arrives at the same conclusion: (p. 74) "Caeterum haud immerito quispiam dubitaverit quam ob rem Architectus Heronis nostri nomen silentio praeterierit. Nos ideo factuni putamus quod ille Ctesibio utpote inventori ea tribuere maluerit quae ab Herone locupletiora et illustriora quam ipse a magistro accepisset evulgata fuere."

Treatise on Pneumatics.