The Pneumatics of Hero of Alexandria

Part 1

TRANSCRIBER’S NOTE

Italic text is denoted by underscores.

Footnote anchors are denoted by [number], and the footnotes have been placed at the end of the chapter.

A superscript is denoted by ^x or ^{xx}, for example und^r or 36^{th}.

Corrigenda on page xiv have been applied to the etext except for illustration corrections.

Illustrations without captions have had a description added.

Some minor changes to the text are noted at the end of the book.

INVENTIONS

OF THE

ANCIENTS

HERO OF ALEXANDRIA ]

THE

PNEUMATICS

HERO OF ALEXANDRIA

FROM THE ORIGINAL GREEK

TRANSLATED FOR AND EDITED BY

BENNET WOODCROFT

PROFESSOR OF MACHINERY IN UNIVERSITY

COLLEGE LONDON

LONDON TAYLOR WALTON AND MABERLY UPPER GOWER STREET AND IVY LANE PATERNOSTER ROW 1851

HIS ROYAL HIGHNESS PRINCE ALBERT

PRESIDENT OF THE SOCIETY OF ARTS

This Work

IS BY SPECIAL PERMISSION MOST RESPECTFULLY

DEDICATED

BY HIS ROYAL HIGHNESS’S OBEDIENT AND

VERY HUMBLE SERVANT,

BENNET WOODCROFT.

Part 2

EDITOR’S PREFACE.

While the Editor of the present work was engaged in writing an Analytical History of the Steam-Engine, it became necessary to consult the antient mechanicians to ascertain who were the inventors of the several parts composing that machine: the earliest writer on the subject appeared to be Hero of Alexandria; throughout whose work so many of the elementary parts of all Steam-Engines, and those also of most other machines are mentioned, that it was thought a translation of Hero’s Pneumatics would be acceptable not only to the Engineer but to the scientific world generally.

Although at the commencement of his work, Hero states that he has added his own discoveries to those “handed down by former writers,” yet in no instance has he pointed out any thing which originated with himself; nor is there any statement in the text, except the one I have just quoted, which would lead the reader to any other conclusion than that the whole is a compilation from the works of those who at that period of time were styled the “antient philosophers and mechanicians.”

Those parts of each vessel or instrument which mechanically perform the operations assigned to them are alike, or nearly so, in the four manuscript and the three printed copies of Hero’s works which have been consulted by the Editor; but great diversity of form is given to the vessel in which they are placed. The drawings have been made expressly for this work from the best examples.

The seventy-eighth proposition is the only instance in which there is an omission of the illustrative drawing, and this occurs in all the copies; the two drawings which are now supplied to that proposition have been made from the descriptions given in the text.

For the Translation of Hero from the Greek, the valuable assistance of Mr. J. G. Greenwood, Fellow of University College, London, has been obtained: he is the recently appointed Professor of the Languages and Literature of Greece and Rome, in Owen’s College, Manchester.

It is confidently hoped that this Translation will be found superior to its predecessors in whatever language; and that it will prove not only generally interesting but practically useful.

TRANSLATOR’S PREFACE.

Concerning Hero of Alexandria, 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 Ἥρωνος Κτησιβίου prefixed to another work by Hero on the construction of missiles.

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 the 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: Athenæus (vol. iv. p. 174, edit. Schweighæuser) quotes one Aristocles as saying, in a work περὶ χορῶν, of the water-organ, φασὶ τοῦτο εὑρῆσθαι ὑπὸ Κτησιβίου κουρέως ἐνταῦθα οἰκοῦντος ἐν τῇ Ἀσπενδίᾳ ἐπὶ τοῦ δευτέρου Εὐεργέτου· διαπρέψαι τέ φασι μεγάλως. 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, (Bibi. Græc. 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.): Athenæus Mechanicus, (one of the mechanical writers whose works are printed in the Veterum Mathematicorum Opera), in his treatise περὶ μηχανημάτων, p. 8, speaks of Ctesibius as a contemporary; his words are Κτησίβιος ὁ Ἀσκληνὸς, ὁ ἐν Ἀλεξανδρείᾳ μηχανικός. 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 Schweighæuser, in a note on the passage of Athenæus referred to above: he deems the identification of the patron of Athenæus 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 Athenæus, (ὦ σεμνότατε Μάρκελλε,) 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: Athenæus 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.

The treatise on Pneumatics was first 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 all 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 translation 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.

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