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diff --git a/77400-0.txt b/77400-0.txt new file mode 100644 index 0000000..27c8cd0 --- /dev/null +++ b/77400-0.txt @@ -0,0 +1,4127 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 77400 *** + +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. + + + + +[Illustration: + + INVENTIONS + + OF THE + + ANCIENTS + + HERO OF ALEXANDRIA +] + + + + + THE + + PNEUMATICS + + OF + + HERO OF ALEXANDRIA + + FROM THE ORIGINAL GREEK + + TRANSLATED FOR AND EDITED BY + + BENNET WOODCROFT + + PROFESSOR OF MACHINERY IN UNIVERSITY + + COLLEGE LONDON + + [Illustration: Decorative divider] + + LONDON + TAYLOR WALTON AND MABERLY + UPPER GOWER STREET AND IVY LANE PATERNOSTER ROW + 1851 + + + + + TO + + 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. + + + + +[Illustration: Decorative border with depictions of cheribs sailing, +making pottery and sculpting stone] + + + + +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. + + + + +[Illustration: Decorative border of curled leafy vines.] + + + + +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[1] 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,[2] 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. + +The other treatises of Hero are:—1. On the construction of slings. 2. +On the construction of missiles. 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. +Schweighæuser 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, τέλος τῶν +Ἀρχιμήδους Βελοποιΐκῶν, τῶν ἐξηγηθέντων παρὰ Ἥρωνος Κτησιβίου. 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 hæc sola +ratio Ctesibii fertur exquisita, sed etiam plures et variis generibus +ab eo liquore pressionibus coacto spiritus efferre ab natura mutuatos +effectus ostenduntur, uti merularum aquæ motu voces, atque engibata, +quæ bibentia tandem movent sigilla, cæteraque quæ delectationibus +oculorum et aurium 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,[3] seems to have had no knowledge of Hero’s Pneumatics, as both +the forcing-pump and the water-organ 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.[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 + + 4. Siphon which is capable of discharging a greater or less + quantity of Liquid with uniformity 17 + + 5. A Vessel for withdrawing Air from a Siphon 18 + + 6. A Vessel for retaining or discharging a Liquid at pleasure 19 + + 7. A Vessel for discharging Liquids of different temperatures at + pleasure 20 + + 8. A Vessel for discharging Liquids in varying proportions 22 + + 9. A Water Jet produced by mechanically compressed Air 23 + + 10. A Valve for a Pump 25 + + 11. Libations on an Altar produced by Fire 26 + + 12. A Vessel from which the contents flow when filled to a certain + height 27 + + 13. Two Vessels from which the contents flow, by a Liquid being + poured into one only 28 + + 14. A Bird made to whistle by flowing Water 29 + + 15. Birds made to sing and be silent alternately by flowing + Water 31 + + 16. Trumpets sounded by flowing Water 32 + + 17. Sounds produced on the opening of a Temple Door 33 + + 18. Drinking-Horn from which either Wine or Water will flow 34 + + 19. A Vessel containing a Liquid of uniform height, although a + Stream flows from it 35 + + 20. A Vessel which remains full, although Water be drawn from it 36 + + 21. Sacrificial Vessel which flows only when Money is introduced 37 + + 22. A Vessel from which a variety of Liquids may be made to flow + through one Pipe 38 + + 23. A Flow of Wine from one Vessel, produced by Water being poured + into another 39 + + 24. A Pipe from which flows Wine-and-Water in varying + proportions 40 + + 25. A Vessel from which Wine flows in proportion as Water is + withdrawn 41 + + 26. A Vessel from which Wine flows in proportion as Water is + poured into another 43 + + 27. The Fire-Engine 44 + + 28. An Automaton which drinks at certain times only, on a Liquid + being presented to it 46 + + 29. An Automaton which may be made to drink at any time, on a + Liquid being presented to it 47 + + 30. An Automaton which will drink any quantity that may be + presented to it 48 + + 31. A Wheel in a Temple, which, on being turned liberates + purifying Water 49 + + 32. A Vessel containing different Wines, any one of which may be + liberated by placing a certain Weight in a Cup 50 + + 33. A self-trimming Lamp 52 + + 34. A Vessel from which Liquid may be made to flow, on any portion + of Water being poured into it 53 + + 35. A Vessel which will hold a certain quantity of Liquid when the + supply is continuous, will only receive a portion of such + Liquid if the supply is intermittent 54 + + 36. A Satyr pouring Water from a Wine-skin into a full + Washing-Basin, without making the contents overflow 55 + + 37. Temple Doors opened by Fire on an Altar 57 + + 38. Other intermediate means of opening Temple Doors by Fire on an + Altar 59 + + 39. Wine flowing from a Vessel may be arrested on the Introduction + of Water, but, when the Supply of Water ceases, the Wine flows + again 60 + + 40. On an Apple being lifted, Hercules shoots a Dragon which then + hisses 62 + + 41. A Vessel from which uniform Quantities only of Liquid can be + poured 64 + + 42. A Water Jet actuated by compressed Air from the Lungs 65 + + 43. Notes from a Bird produced at intervals by an intermittent + Stream of Water 66 + + 44. Notes produced from several Birds in succession, by a Stream + of Water 67 + + 45. A Jet of Steam supporting a Sphere 68 + + 46. The World represented in the Centre of the Universe 68 + + 47. A Fountain which trickles by the Action of the Sun’s Rays 69 + + 48. A Thyrsus made to whistle by being submerged in Water 70 + + 49. A Trumpet, in the Hands of an Automaton, sounded by + compressed Air 71 + + 50. The Steam-Engine 72 + + 51. A Vessel from which flowing Water may be stopped at pleasure 73 + + 52. A Drinking-Horn in which a peculiarly formed Siphon is fixed 74 + + 53. A Vessel in which Water and Air ascend and descend + alternately 75 + + 54. Water driven from the Mouth of a Wine-skin in the Hands of a + Satyr, by means of compressed Air 76 + + 55. A Vessel, out of which Water flows as it is poured in, but if + the supply is withheld, Water will not flow again, until the + Vessel is half filled; and on the supply being again stopped, + it will not then flow until the Vessel is filled 77 + + 56. A Cupping-Glass, to which is attached, an Air-exhausted + Compartment 79 + + 57. Description of a Syringe 80 + + 58. A Vessel from which a Flow of Wine can be stopped, by pouring + into it a small Measure of Water 81 + + 59. A Vessel from which Wine or Water may be made to flow, + separately or mixed 82 + + 60. Libations poured on an Altar, and a Serpent made to hiss, by + the Action of Fire 83 + + 61. Water flowing from a Siphon ceases on surrounding the End of + its longer Side with Water 85 + + 62. A Vessel which emits a Sound when a Liquor is poured from it 86 + + 63. A Water-Clock, made to govern the quantities of Liquid flowing + from a Vessel 87 + + 64. A Drinking-Horn from which a Mixture of Wine and Water, or + pure Water may be made to flow alternately or together, at + pleasure 89 + + 65. A Vessel from which Wine or Water may be made to flow + separately or mixed 90 + + 66. Wine discharged into a Cup in any required quantity 91 + + 67. A Goblet into which as much Wine flows as is taken out 92 + + 68. A Shrine over which a Bird may be made to revolve and sing by + Worshippers turning a Wheel 93 + + 69. A Siphon fixed in a Vessel from which the Discharge shall + cease at will 94 + + 70. Figures made to dance by Fire on an Altar 95 + + 71. A Lamp in which the Oil can be raised by Water contained + within its Stand 96 + + 72. A Lamp in which the Oil is raised by blowing Air into it 98 + + 73. A Lamp in which the Oil is raised by Water as required 99 + + 74. A Steam-Boiler from which a hot-Air blast, or hot-Air mixed + with Steam is blown into the Fire, and from which hot Water + flows on the introduction of cold 100 + + 75. A Steam-Boiler from which either a hot Blast may be driven + into the Fire, a Blackbird made to sing, or a Triton to blow + a Horn 103 + + 76. An Altar Organ blown by manual Labour 105 + + 77. An Altar Organ blown by the agency of a Wind-mill 108 + + 78. An Automaton, the head of which continues attached to the + body, after a knife has entered the neck at one side, passed + completely through it, and out at the other; the animal will + drink immediately after the operation 109 + + + + +[Illustration: Decorative border with an anvil in the middle and a pair +of cheribs working with tools on each side.] + + + + +A TREATISE ON PNEUMATICS. + + +The investigation of the properties of Atmospheric Air having been +deemed worthy of close attention by the ancient philosophers and +mechanists, the former deducing them theoretically, the latter +from the action of sensible bodies, we also have thought proper to +arrange in order what has been handed down by former writers, and to +add thereto our own discoveries: a task from which much advantage +will result to those who shall hereafter devote themselves to the +study of mathematics. We are further led to write this work from the +consideration that it is fitting that the treatment of this subject +should correspond with the method given by us in our treatise, in four +books, on water-clocks. For, by the union of air, earth, fire and +water, and the concurrence of three, or four, elementary principles, +various combinations are effected, some of which supply the most +pressing wants of human life, while others produce amazement and alarm. + +But, before proceeding to our proper subject, we must treat of the +vacuum. Some assert that there is absolutely no vacuum; others that, +while no continuous vacuum is exhibited in nature, it is to be found +distributed in minute portions through air, water, fire and all +other substances: and this latter opinion, which we will presently +demonstrate to be true from sensible phenomena, we adopt. Vessels which +seem to most men empty are not empty, as they suppose, but full of +air. Now the air, as those who have treated of physics are agreed, +is composed of particles minute and light, and for the most part +invisible. If, then, we pour water into an apparently empty vessel, +air will leave the vessel proportioned in quantity to the water which +enters it. This may be seen from the following experiment. Let the +vessel which seems to be empty be inverted, and, being carefully kept +upright, pressed down into water; the water will not enter it even +though it be entirely immersed: so that it is manifest that the air, +being matter, and having itself filled all the space in the vessel, +does not allow the water to enter. Now, if we bore the bottom of the +vessel, the water will enter through the mouth, but the air will escape +through the hole. Again, if, before perforating the bottom, we raise +the vessel vertically, and turn it up, we shall find the inner surface +of the vessel entirely free from moisture, exactly as it was before +immersion. Hence it must be assumed that the air is matter. The air +when set in motion becomes wind, (for wind is nothing else but air +in motion), and if, when the bottom of the vessel has been pierced +and the water is entering, we place the hand over the hole, we shall +feel the wind escaping from the vessel; and this is nothing else but +the air which is being driven out by the water. It is not then to be +supposed that there exists in nature a distinct and continuous vacuum, +but that it is distributed in small measures through air and liquid +and all other bodies. Adamant alone might be thought not to partake of +this quality, as it does not admit of fusion or fracture, and, when +beaten against anvils or hammers, buries itself in them entire. This +peculiarity however is due to its excessive density: for the particles +of fire, being coarser than the void spaces in the stone, do not pass +through them, but only touch the outer surface; consequently, as they +do not penetrate into this, as into other substances, no heat results. +The particles of the air are in contact with each other, yet they do +not fit closely in every part, but void spaces are left between them, +as in the sand on the sea shore: the grains of sand must be imagined +to correspond to the particles of air, and the air between the grains +of sand to the void spaces between the particles of air. Hence, when +any force is applied to it, the air is compressed, and, contrary to +its nature, falls into the vacant spaces from the pressure exerted on +its particles: but when the force is withdrawn, the air returns again +to its former position from the elasticity of its particles, as is the +case with horn shavings and sponge, which, when compressed and set +free again, return to the same position and exhibit the same bulk. +Similarly, if from the application of force the particles of air be +divided and a vacuum be produced larger than is natural, the particles +unite again afterwards; for bodies will have a rapid motion through a +vacuum, where there is nothing to obstruct or repel them, until they +are in contact. Thus, if a light vessel with a narrow mouth be taken +and applied to the lips, and the air be sucked out and discharged, the +vessel will be suspended from the lips, the vacuum drawing the flesh +towards it that the exhausted space may be filled. It is manifest from +this that there was a continuous vacuum in the vessel. The same may be +shown by means of the egg-shaped cups used by physicians, which are of +glass,[5] and have narrow mouths. When they wish to fill these with +liquid, after sucking out the contained air, they place the finger on +the vessel’s mouth and invert it into the liquid; then, the finger +being withdrawn, the water is drawn up into the exhausted space, though +the upward motion is against its nature. Very similar is the operation +of cupping-glasses, which, when applied to the body, not only do not +fall though of considerable weight, but even draw the contiguous matter +toward them through the apertures of the body. The explanation is that +the fire placed in them consumes and rarefies the air they contain, +just as other substances, water, air or earth are consumed and pass +over into more subtle substances. + +That something is consumed by the action of fire is manifest from +coal-cinders, which, preserving the same bulk as they had before +combustion, or nearly so, differ very much in weight. The consumed +parts pass away with the smoke into a substance of fire or air or +earth: the subtlest parts pass into the highest region where fire is; +the parts somewhat coarser than these into air, and those coarser +still, having been borne with the others a certain space by the +current, descend again into the lower regions and mingle with earthy +substances. Water also, when consumed by the action of fire, is +transformed into air; for the vapour arising from cauldrons placed +upon flames is nothing but the evaporation from the liquid passing +into air. That fire, then, dissolves and transforms all bodies grosser +than itself is evident from the above facts. Again, in the exhalations +that rise from the earth the grosser kinds of matter are changed into +subtler substances; for dew is sent up from the evaporation of the +water contained in the earth by exhalation; and this exhalation is +produced by some igneous substance, when the sun is under the earth +and warms the ground below, especially if the soil be sulphureous or +bituminous, and the ground thus warmed increases the exhalation. The +warm springs found in the earth are due to the same cause. The lighter +portions of the dew, then, pass into air; the grosser, after being +borne upwards for a certain space from the force of the exhalation, +when this has cooled at the return of the sun, descend again to the +surface. + +Winds are produced from excessive exhalation, whereby the air is +disturbed and rarefied, and sets in motion the air in immediate +contact with it. This movement of the air, however, is not everywhere +of uniform velocity: it is more violent in the neighbourhood of the +exhalation, where the motion began; fainter at a greater distance from +it: just as heavy bodies, when rising, move more rapidly in the lower +region where the propelling force is, and more slowly in the higher; +and when the force which originally propelled them no longer acts upon +them, they return to their natural position, that is, to the surface +of the earth. If the propelling force continued to urge them onward +with equal velocity, they would never have stopped; but now the force +gradually ceases, being as it were expended, and the speed of the +motion ceases with it. + +Water, again, is transformed into an earthy substance: if we pour +water into an earthy and hollow place, after a short time the water +disappears, being absorbed by the earthy substance, so that it mingles +with, and is actually transformed into, earth. And if any one says +that it is not transformed or absorbed by the earth, but is drawn +out by heat, either of the sun or some other body, he shall be shewn +to be mistaken: for if the same water be put into a vessel of glass, +or bronze, or any other solid material, and placed in the sun, for a +considerable time it is not diminished except in a very small degree. +Water, therefore, is transformed into an earthy substance: indeed, +slime and mud are transformations of water into earth. + +Moreover, the more subtle substance is transformed into the grosser; +as in the case of the flame of a lamp dying out for want of oil,—we +see it for a time borne upwards and, as it were, striving to reach its +proper region, that is, the highest of all above the atmosphere, till, +overpowered by the mass of intervening air, it no longer tends to its +kindred place, but, as though mixed and interwoven with the particles +of air, becomes air itself. The same may be observed with air. For, if +a small vessel containing air and carefully closed be placed in water +with the mouth uppermost, and then, the vessel being uncovered, the +water be allowed to rush in, the air escapes from the vessel; but, +being overpowered by the mass of water, it mingles with it again and is +transformed so as to become water. + +When, therefore, the air in the cupping-glasses, being in like manner +consumed and rarefied by fire, issues through the pores in the sides +of the glass, the space within is exhausted and draws towards it the +matter adjacent, of whatever kind it may be. But, if the cupping-glass +be slightly raised, the air will enter the exhausted space and no more +matter will be drawn up. + +They, then, who assert that there is absolutely no vacuum may invent +many arguments on this subject, and perhaps seem to discourse most +plausibly though they offer no tangible proof. If, however, it be +shewn by an appeal to sensible phenomena that there is such a thing +as a continuous vacuum, but artificially produced; that a vacuum +exists also naturally, but scattered in minute portions; and that by +compression bodies fill up these scattered vacua, those who bring +forward such plausible arguments in this matter will no longer be able +to make good their ground. + +Provide a spherical vessel, of the thickness of metal plate so as not +to be easily crushed, containing about 8 cotylæ (2 quarts). When this +has been tightly closed on every side, pierce a hole in it, and insert +a siphon, or slender tube, of bronze, so as not to touch the part +diametrically opposite to the point of perforation, that a passage +may be left for water. The other end of the siphon must project about +3 fingers’ breadth (2 in.) above the globe, and the circumference +of the aperture through which the siphon is inserted must be closed +with tin applied both to the siphon and to the outer surface of the +globe, so that when it is desired to breathe through the siphon no +air may possibly escape from the vessel. Let us watch the result. The +globe, like other vessels commonly said to be empty, contains air, +and as this air fills all the space within it and presses uniformly +against the inner surface of the vessel, if there is no vacuum, as +some suppose, we can neither introduce water nor more air, unless the +air contained before make way for it; and if by the application of +force we make the attempt, the vessel, being full, will burst sooner +than admit it. For the particles of air cannot be condensed, as there +must in that case be interstices between them, by compression into +which their bulk may become less; but this is not credible if there +is no vacuum: nor again, as the particles press against one another +throughout their whole surface and likewise against the sides of the +vessel, can they be pushed away so as to make room if there is no +vacuum. Thus in no way can anything from without be introduced into +the globe unless some portion of the previously contained air escape; +if, that is to say, the whole space is closely and uniformly filled, +as the objectors suppose. And yet, if any one, inserting the siphon +in his mouth, shall blow into the globe, he will introduce much wind +without any of the previously contained air giving way. And, this being +the uniform result, it is clearly shewn that a condensation takes place +of the particles contained in the globe into the interspersed vacua. +The condensation however is effected artificially by the forcible +introduction of air. Now if, after blowing into the vessel, we bring +the hand close to the mouth, and quickly cover the siphon with the +finger, the air remains the whole time pent up in the globe; and on +the removal of the finger the introduced air will rush out again with +a loud noise, being thrust out, as we stated, by the expansion of +the original air which takes place from its elasticity. Again, if we +draw out the air in the globe by suction through the siphon, it will +follow abundantly, though no other substance take its place in the +vessel, as has been said in the case of the egg. By this experiment +it is completely proved that an accumulation of vacuum goes on in the +globe; for the particles of air left behind cannot grow larger in the +interval so as to occupy the space left by the particles driven out. +For if they increase in magnitude when no foreign substance can be +added, it must be supposed that this increase arises from expansion, +which is equivalent to a re-arrangement of the particles through the +production of a vacuum. But it is maintained that there is no vacuum; +the particles therefore will not become larger, for it is not possible +to imagine for them any other mode of increase. It is clear, then, from +what has been said that certain void spaces are interspersed between +the particles of the air, into which, when force is applied, they fall +contrary to their natural action. + +The air contained in the vessel inverted in water does not undergo +much compression, for the compressing force is not considerable, +seeing that water, in its own nature, possesses neither weight nor +power of excessive pressure. Whence it is that, though divers to the +bottom of the sea support an immense weight of water on their backs, +respiration is not compelled by the water, though the air contained in +their nostrils is extremely little. It is worth while here to examine +what reason is given why those who dive deep, supporting on their +backs an immense weight of water, are not crushed. Some say that it +is because water is of uniform weight: but these give no reason why +divers are not crushed by the water above. The true reason may be shewn +as follows. Let us imagine the column of liquid which is directly over +the surface of the object under pressure, (in immediate contact with +which the water is,) to be a body of the same weight and form as the +superincumbent liquid, and that this is so placed in the water that its +under surface coincides with the surface of the body pressed, resting +upon it in the same manner as the previously superincumbent liquid, +with which it exactly corresponds. It is clear, then, that this body +does not project above the liquid in which it is immersed, and will +not sink beneath its surface. For Archimedes has shewn, in his work +on ‘Floating Bodies,’ that bodies of equal weight with any liquid, +when immersed in it, will neither project above nor sink beneath its +surface: therefore they will not exert pressure on objects beneath. +Again, such a body, if all objects which exert pressure from above be +removed, remains in the same place; how then can a body which has no +tendency downward exert pressure? Similarly, the liquid displaced by +the body will not exert pressure on objects beneath; for, as regards +rest and motion, the body in question does [not] differ from the liquid +which occupies the same space. + +Again, that void spaces exist may be seen from the following +considerations: for, if there were not such spaces, neither light, +nor heat, nor any other material force could penetrate through water, +or air, or any body whatever. How could the rays of the sun, for +example, penetrate through water to the bottom of the vessel? If there +were no pores in the fluid, and the rays thrust the water aside by +force, the consequence would be that full vessels would overflow, +which however does not take place. Again, if the rays thrust the water +aside by force, it would not be found that some were reflected while +others penetrated below; but now all those rays that impinge upon the +particles of the water are driven back, as it were, and reflected, +while those that come in contact with the void spaces, meeting with +but few particles, penetrate to the bottom of the vessel. It is clear, +too, that void spaces exist in water from this, that, when wine is +poured into water, it is seen to spread itself through every part +of the water, which it would not do if there were no vacua in the +water. Again, one light traverses another; for, when several lamps are +lighted, all objects are brilliantly illuminated, the rays passing +in every direction through each other. And indeed it is possible to +penetrate through bronze, iron, and all other bodies, as is seen in the +instance of the marine torpedo. + +That a continuous vacuum can be artificially produced has been shewn +by the application of a light vessel to the mouth, and by the egg of +physicians. With regard, then, to the nature of the vacuum, though +other proofs exist, we deem those that have been given, and which are +founded on sensible phenomena, to be sufficient. It may, therefore, +be affirmed in this matter that every body is composed of minute +particles, between which are empty spaces less than the particles of +the body, (so that we erroneously say that there is no vacuum except +by the application of force, and that every place is full either of +air, or water, or some other substance), and, in proportion as any one +of these particles recedes, some other follows it and fills the vacant +space: that there is no continuous vacuum except by the application of +some force: and again, that the absolute vacuum is never found, but is +produced artificially. + +These things having been clearly explained, let us treat of the +theorems resulting from the combination of these principles; for, by +means of them, many curious and astonishing kinds of motion may be +discovered. After these preliminary considerations we will begin by +treating of the bent siphon, which is most useful in many ways in +Pneumatics. + +FOOTNOTES: + +[5] “Glass working was practised by the ancient Egyptians at a very +early period of their national existence. Sir J. G. Wilkinson, in +his able work on the _Manners and Customs of the ancient Egyptians_, +has adduced three distinct proofs that the art of Glass working was +practised in Egypt before the Exodus of the children of Israel from +that land, three thousand five hundred years ago. At Beni Hassan +are two paintings representing Glass blowers at work, and from the +hieroglyphics accompanying them they are shown to have been executed +in the reign of the first Osirtasen at the early date above mentioned. +Such was the skill of the Egyptians in glass making, that they +successively counterfeited the Amethyst and other precious stones +worn as ornaments for the person. Winckelmann, a high authority, is +of opinion that glass was employed more frequently in ancient than in +modern times; it was used by the Egyptians even for coffins; (_within +the year 1847 a process was patented in England for making Coffins of +Glass_) they also employed it not only for drinking vessels but for +Mosaic work, the figures of deities, and sacred emblems, in which they +attained excellent workmanship, and surprising brilliancy of colour. +“It is certain that the glass houses of Alexandria were celebrated +among the ancients for the skill and ingenuity of their workmen; and +from thence the Romans, who did not acquire a knowledge of the art till +a later period, procured all their Glass ware. + +[Illustration: Egyptian painting of glassblowers at a fire] + +[Illustration: Egyptian painting of glassblowers blowing a large +vessel.] + +“Most of the large cinerary vases in the British Museum, found in +Roman barrows which contained bones and bone-ashes, are, probably, the +production of extensive Egyptian or Roman works: they are large, and of +excellent form and workmanship: but the Glass is somewhat impure, of a +greenish tint, has numerous globules and striæ, and is not unlike the +modern common crown or sheet glass in quality. + +“We have incidentally mentioned the discovery of Glass at Pompeii. +Glass vessels have also been found among the ruins of Herculaneum: and +it appears that Glass was used for admitting light to dwellings in +Pompeii. + +“Mr. Auldjo, of Noel house, Kensington, who resided several years at +Naples, states, that he has seen glass in the window-frames of some of +the houses of Pompeii. + +“Mr. Roach Smith has a specimen of ancient flat Glass such as he +believes to have been used by the Romans, or their predecessors for +windows.”—_Curiosities of Glass making by_ APSLEY PELLAT, London, 1849. + +Mr. Layard in his interesting work on Nineveh, 1849, London, in Vol. I, +page 342, says: “I took the instrument, and, working cautiously myself, +was rewarded by the discovery of two small vases, one in alabaster, +the other in glass (both in the most perfect preservation) of elegant +shape, and admirable workmanship. Each bore the name and title of the +Khorsabad King, written in two different ways, as in the inscriptions +of Khorsabad.” + + + + +_No. 1. The bent Siphon._ + + +[Illustration: Diagram of apparatus as described in text] + +Let A B C, (fig. 1), be a bent siphon, or tube, of which the leg A B is +plunged into a vessel D E containing water. If the surface of the water +is in F G, the leg of the siphon, A B, will be filled with water as +high as the surface, that is, up to H, the portion H B C remaining full +of air. If, then, we draw off the air by suction through the aperture +C, the liquid also will follow from the impossibility, explained above, +of a continuous vacuum. And, if the aperture C be level with the +surface of the water, the siphon, though full, will not discharge the +water, but will remain full: so that, although it is contrary to nature +for water to rise, it has risen so as to fill the tube A B C; and the +water will remain in equilibrium, like the beams of a balance, the +portion H B being raised on high, and the portion B C suspended. But if +the outer mouth of the siphon be lower than the surface F G, as at K, +the water flows out; for the liquid in K B, being heavier, overpowers +and draws toward it the liquid in B H. The discharge, however, +continues only until the surface of the water is on a level with the +mouth K, when, for the same reason as before, the efflux ceases. But +if the outer mouth of the tube be lower than K, as at L, the discharge +continues until the surface of the water reaches the mouth A. If then +we wish all the water in the vessel to be drawn out, we must depress +the siphon so far that the mouth A may reach the bottom of the vessel, +leaving only a passage for the water. + +Now some writers have given the above explanation of the action of the +siphon, saying that the longer leg, holding more, attracts the shorter. +But that such an explanation is incorrect, and that he who believes so +would be greatly mistaken if he were to attempt to raise water from a +lower level, we may prove as follows. Let there be a siphon with its +inner leg longer and narrow, and the outer much less in length but +broader so as to contain more water than the longer leg. Then, having +first filled the siphon with water, plunge the longer leg into a vessel +of water or a well. Now, if we allow the water to flow, the outer leg, +containing more than the inner, should draw the water out of the longer +leg, which will at the same time draw up the water in the well; and +the discharge having begun will exhaust all the water or continue for +ever, since the liquid without is more than that within. But this is +not found to be the case; and therefore the alleged cause is not the +true one. Let us then examine into the natural cause. The surface of +every liquid body, when at rest, is spherical and concentric with that +of the earth; and, if the liquid be not at rest, it moves until it +attains such a surface. If then we take two vessels and pour water into +each, and, after filling the siphon and closing its extremities with +the fingers, insert one leg into one vessel plunging it beneath the +water, and the other into the other, all the water will be continuous, +for each of the liquids in the vessels communicates with that in the +siphon. If, then, the surfaces of the liquids in the vessels were at +the same level before, they will both remain at rest when the siphon is +plunged in. But if they were not, as soon as the water is continuous +it must inevitably flow into the lower vessel through the channel of +communication, until either all the water in both vessels stands at the +same height, or one of the vessels is emptied. Suppose that the liquids +stand at the same height; they will of course be at rest, so that the +liquid in the siphon will also be at rest. If, then, the siphon be +conceived to be intersected by a plane in the surface of the liquids in +the vessels, even now the liquid in the siphon will be at rest, and, if +raised without being inclined to either side, it will again be at rest, +and that, whether the siphon is of equal breadth throughout or one leg +is much larger than the other. For the reason why the liquid remained +at rest did not lie in this, but in the fact that the apertures of +the siphon were at the same level. The question now arises why, when +the siphon is raised, the water is not borne down by its own weight, +having beneath it air which is lighter than itself. The answer is that +a continuous void cannot exist; so that, if the water is to descend, +we must first fill the upper part of the siphon, into which no air +can possibly force its way. But if we pierce a hole in the upper part +of the siphon, the water will immediately be rent in sunder the air +having found a passage. Before the hole is bored, the liquid in the +siphon, resting on the air beneath, tends to drive it away, but the air +having no means of escape does not allow the water to pass out: when +however the air has obtained a passage through the hole, being unable +to sustain the pressure of the water, it escapes. It is from the same +cause that, by means of a siphon, we can suck wine upwards, though this +is contrary to the nature of a liquid; for, when we have received into +the body the air which was in the siphon, we become fuller than before, +and a pressure is exerted on the air contiguous to us, and this in turn +presses on the atmosphere at large, until a void has been produced at +the surface of the wine, and then the wine undergoing pressure itself +will pass into the exhausted space of the siphon; for there is no other +place into which it can escape from the pressure. It is from this cause +that its unnatural upward movement arises. + +[Illustration: Two overlaping circles, A, B, C are on the left circle. +F, B, D are on the right, a is a center point, F is on a line from a +to A. There is a line from a to B, the intersection point of the two +circles.] + +That the water in the siphon will rest when its surface is spherical +and concentric with that of the earth may be shewn otherwise. It is +required to prove that a liquid is stationary when its surface is +spherical and concentric with that of the earth. If possible let it +not be stationary; it will of course become so after being moved; let +it then have become stationary. Its surface will now be spherical +and concentric with that of the earth, and it will cut the former +surface; for, when the same liquid has taken two positions, there must +be a line of intersection common to both. Let both surfaces be cut by +a plane passing through the centre of the earth; the intersections +will be the circumferences of circles concentric with the earth. Let +these circumferences be A B C and F B D, (fig. 1 a.) Join B G; B G is +equal to each of the lines G F, G A, which is absurd. The liquid will +therefore be in equilibrium. + + + + +2. _Concentric or inclosed Siphon._ + + +[Illustration: Diagram of apparatus as described in text] + +There is another kind of siphon called _the concentric_ or _inclosed +diabetes_, the principle of which is the same as that of the bent +siphon. As before, let there be a vessel, A B (fig. 2), containing +water. Through its bottom insert a tube, C D, soldered into the bottom +and projecting below. Let the aperture C of the siphon approach to the +mouth of the vessel A B, and let another tube, E F, inclose the tube +C D, the distance between the tubes being every where equal, and the +mouth of the outer tube being closed by a plate, E G, a little above +the mouth C. The lower opening of the tube E F must be so far removed +from the bottom of the vessel as to leave a passage for the water. +These arrangements being completed, if we exhaust, by suction through +the mouth D, the air in the tube C D, we shall draw into it the water +in the vessel A B, so that it will flow out through the projection of +the siphon until the water is exhausted. For the air contained between +the liquid and the tube E F, being but little, can pass into the tube +C D, and the water can then be drawn after it. And the water will +not cease flowing because of the projection of the siphon below:—if, +indeed, the tube E F were removed, the discharge would cease on the +surface of the water arriving at C, in spite of the projection below; +but when E F is entirely immersed no air can enter the siphon in place +of that drawn off, since the air which enters the vessel takes the +place of the water as it passes out:—the discharge then, will not +cease, for the whole of the outer aperture of the tube, where the +water issues forth, is always lower than the surface of the water in +the vessel, and, as one level can never be attained, all the water +is drained off, attraction being exerted by the deeper column. If we +do not choose to draw out the air in the tube C D by suction, water +may be poured into the vessel A B until, when it has risen above C, a +discharge begins through C D. In this case, again, all the water in the +vessel will be drawn out. This instrument is called, as we said before, +_the inclosed siphon_, or _the inclosed diabetes_. + +It is evident from what has been proved above that as long as the +siphon is stationary the stream through it will be of irregular +velocity, for the result is the same as in a discharge through a hole +pierced in the bottom of a vessel, where the stream is irregular from +the pressure of a greater weight on the discharge at its commencement, +and, of a less, as the contents of the vessel are reduced. In like +manner, in proportion as the excess of the outer leg of the siphon is +greater, the velocity of the stream is greater; for a greater pressure +is exerted on the discharge than when the projection of the outer leg +below the surface of the water in the vessel is less. Therefore we +have said that the discharge through the siphon is always of variable +velocity. But we must contrive a siphon in which the velocity of the +discharge shall be uniform. + + + + +3. _Uniform discharge Siphon._ + + +[Illustration: Diagram of apparatus as described in text] + +Let there be a vessel, A B, (fig. 3.) containing water, on which a +small basin, C D, floats, having its mouth covered with the lid C D. +Through this lid and the bottom of the basin insert one leg of the +siphon soldering it into the holes with tin. Let the other leg be +outside the vessel A B, having its mouth lower than the surface of +the water in A B. If we draw the air in the siphon through the outer +extremity, the water will at once follow because of the impossibility +of a continuous vacuum in the siphon; and the siphon, having begun to +flow, flows on until it has exhausted all the water in the vessel: +but the discharge will be uniform, since the projection of the outer +leg below the surface of the water does not vary; for, as the vessel +becomes empty, the basin sinks with the siphon. The greater the excess +of the outer leg the greater will be the velocity of the discharge, yet +still uniform. In the figure, E F G is the siphon described, and the +surface of the water is in the line H K. + + + + +4. _Siphon which is capable of discharging a greater or less quantity +of Liquid with uniformity._ + + +[Illustration: Diagram of apparatus as described in text] + +By the following arrangement we can produce a discharge at once uniform +and variable; that is, a discharge in which, for a certain time at +pleasure, the stream continues uniform from the beginning, and again, +for any other period, is slower or quicker than before, but still +uniform with itself. As before, let A B (fig. 4.) be a vessel of water, +and C D a basin. Into the lid and bottom of the basin solder a tube L +M wider than the inner leg of the siphon. On the lid place a wooden +frame, C N X D, consisting of two upright pieces and a third lying +across them on the top. In the inner sides of the upright pieces let +grooves be cut down their whole length, along which another piece O P +is to move freely. Let R S be a screw, working perpendicularly in the +direction of the lid C D, and passing through a hole in O P: in O P let +a pin be so fixed as to enter the spiral thread of the screw. The screw +must project above N X, and a handle be fastened to its top by which +to turn it, and by this means O P can be raised or lowered. Let the +inner leg of the siphon be fixed in O P, and pass through the tube L +M, so that its mouth may dip into the water in the vessel. Now if, as +before, we draw off the liquid through the outer mouth, the siphon will +flow with a uniform stream until the whole be exhausted. And when it +is wished that a quicker stream should be produced through the siphon, +but uniform with itself, let the screw be turned so as to lower the +board O P; for then the excess of the outer leg is increased, and thus +the stream is still of uniform velocity, but quicker than before. If a +still greater velocity is desired, turn the screw again, so as to lower +O P still further; and if a less velocity is sought, let O P be raised. +Thus a discharge is produced through a siphon in one sense uniform, in +another variable. + + + + +5. _A vessel for withdrawing Air from a Siphon._ + + +[Illustration: Diagram of apparatus as described in text] + +To avoid the necessity of drawing off the water through the mouth, +which is only possible in very small siphons, the following contrivance +may be used. Take a double tube (fig. 5) one part of which fits into +the other, and attach the smaller part to the outer leg of the siphon, +so that the discharge may pass through it. Let T N be the smaller tube, +and Q U the greater, which must be previously fitted tightly into a +vessel, W Y, containing somewhat more water than the siphon will hold, +and having an outlet, Z, at the bottom. When it is wished to draw off +the water in A B, close the outlet of W Y with the finger, then apply +the larger tube Q U to the smaller, and leave the outlet Z free. As +the vessel W Y becomes empty the air in the siphon will pass into the +exhausted space, and the liquid in A B will follow so as to fill the +siphon: then remove the vessel W Y, and let the siphon run. + +To act properly the siphon must be perpendicular; and this may be +secured by fixing two straight bars to the lip of the vessel A B, and +placing the inner leg of the siphon between them so as to touch each +of the bars: then fasten a small bar crosswise on each side of the leg +of the siphon, so as to touch the former bars within. Thus, if the +smaller bars touch the larger, the siphon will neither lean sideways +nor forwards, but will hang perpendicularly. + + + + +6. _A Vessel for retaining or discharging a Liquid at pleasure._ + + +[Illustration: Diagram of apparatus as described in text] + +Let us now proceed to construct the necessary instruments, beginning +with the less important, as from the elements. The following is a +contrivance of use in pouring out wine. A hollow globe of bronze is +provided, such as A B (fig. 6) pierced in the lower part with numerous +small holes like a sieve. At the top let there be a tube, C D, the +upper extremity of which is open, communicating with and soldered into +the globe. When it is desired to pour out wine, with one hand grasp the +tube C D near the mouth C, and plunge the globe into the wine until +it is wholly immersed. The wine enters through the holes, and the air +within, being driven out, passes through the tube C D: and if, pressing +the thumb on the aperture C, you lift the globe out of the wine, the +wine contained in the globe will not flow out, as no air can enter to +supply the vacuum, for the only entrance is through the mouth C, which +is closed by the thumb. When, then, we desire to let the wine flow, we +remove the finger, and the air, rushing in, fills the vacuum produced. +If we again press the finger on the air-hole C, there will be no +discharge until we once more remove the finger from the vent. We may, +in like manner, dip the globe into hot or cold water, and then retain +or let out the contents at pleasure, until all the water within is +exhausted. If the extremity C of the tube C D is bent, the action will +be the same, and it is then easier to stop the orifice with the finger. + + + + +7. _A Vessel for discharging Liquids of different temperatures at +pleasure._ + + +[Illustration: Diagram of apparatus as described in text] + +By the same means it is possible to discharge from the same globe +both hot and cold water in any quantity. The globe A B (fig. 7) is +constructed as before, but furnished with a perpendicular partition, +C D, dividing it equally. At the top a tube, H F, soldered into the +globe, communicates with the interior; this tube is also furnished +with a partition, C G, a continuation of the partition C D, and its +openings, H, K, must curve over in the directions C and F. +On each side of the partition C D, at the bottom of the globe towards +D, let holes be made like those in a cook’s ladle. When it is desired +to draw hot water, take the apertures H and K by the two fingers and +plunge the globe into hot water, and then unclose one of the vents, +H, that the air in the hemisphere B C D may be driven out through H: +the hot water, entering through the holes, will fill the hemisphere +B C D: again stopping the vent H take the globe out of the water, +and its contents will be retained, as the air has no entrance. Then, +in like manner, plunge the globe into cold water, unclosing the vent +K, and, when the hemisphere A C D is filled, close K and draw the +globe out. The globe is now full of hot and cold water, and when it +is desired to discharge either of these, unclose the proper vent: in +like manner close it again when the discharge is sufficient; and this +may be repeated till the contents are exhausted. In the same way it is +possible to draw up into and discharge from the same vessel wine, and +cold or hot water, and anything else whatever, at any time, and in any +quantity, by making the necessary partitions and orifices through which +the air may enter into each chamber and leave it again. Instead of the +curved outlets, holes may be made in the upper part of the sides of the +tube in various directions; and these holes are of course to be closed +when it is required to shut out the air. That the holes pierced in the +bottom of the vessel may not be seen, both sets may be included in one +channel, so that both streams may appear to flow from the same source. + + + + +8. _A Vessel for discharging Liquids in varying proportions._ + + +[Illustration: Diagram of apparatus as described in text] + +A jar can be made receiving and discharging a greater quantity of +liquid at one time than at another, and in such a way that, when wine +and water are poured into it, it shall discharge at one time pure +water, at another time unmixed wine, and, again, a mixture of the two. +Its construction is as follows. Let A B (fig. 8) be a pitcher having a +partition in the middle, C D. In the partition, near the circumference +of the vessel, let small holes be pierced in a curve, as at E. In the +opposite side of the partition let there be a circular aperture, F, +through which the tube F G H is to be inserted, being soldered into the +partition, and reaching nearly to the bottom of the vessel at G. Let +the other mouth of the tube H issue at the side of the pitcher, under +the handle, and be soldered into the handle which must be hollow, and +have a hole on its outer surface at K, which may be closed with the +finger when necessary. If, then, closing the vent, as before, we pour +any liquid into the jar, the liquid poured into the upper chamber will +remain there, not being able to continue its way through the narrow +holes into the lower chamber, as there is no other outlet for the air +than through the vent K. When, however, we unclose the vent, the liquid +will descend into the chamber beneath, and then the jar will hold more. +If, then, we first pour in wine so as to fill the chamber B C D, and +then, closing the vent, pour water upon it, the two cannot mix, and if +we invert the jar it will emit pure water. But, when we unclose the +vent, the water continuing to flow, the wine will flow out also, since +air can enter through K to fill up the void left; and afterwards the +wine will flow out unmixed. We may also pour in the water first, and +then, stopping the vent, pour wine upon it, so as to pour out wine for +some, wine and water for others, and mere water for those whom we wish +to jest with. + + + + +9. _A Water Jet produced by mechanically compressed Air._ + + +[Illustration: Diagram of apparatus as described in text] + +A hollow globe, or other vessel, may be constructed, into which if +any liquid be poured, it will be forced aloft spontaneously and with +much violence, so as to empty the vessel, though such an upward motion +is contrary to nature. The construction is as follows. Let there be +a globe, containing about 6 cotylæ (3 pints), the sides of which are +of metal plate, strong enough to sustain the pressure that will be +exerted upon them by the air. Let A B (fig. 9) be the globe, resting +on any base C. Through an aperture in the top of the globe insert a +tube, D E, soldered into the globe at the aperture, and projecting +a little above it; and reaching to the other extremity, except an +interval sufficient for the passage of water. At its upper extremity +let the tube D E branch into two tubes, D G and D F, to which two other +pipes, G H K L, F M N X, are fastened transversely, communicating with +D G, D F. Again, into these transverse pipes, and communicating with +them, let another pipe, P O, be fitted, from which a small pipe, R S, +projects perpendicularly, communicating with it, and terminating in a +small orifice at S. If, then, we take hold of R S and turn round the +tube P O, the connection between the corresponding holes will be shut +off, so that the liquid which is to be forced up will have no outlet. +Now, through another aperture in the globe, let another tube, T U Q, +be inserted, closed at the lower extremity Q, and having a hole in the +side near the bottom at W. In this hole must be fixed a valve, such as +the Romans call _assarium_, the construction of which we will explain +presently. Into the tube T U Q insert another tube, Y Z, fitting +tightly. If the tube Y Z be drawn out, and water poured into T U Q, it +will enter the vessel through the aperture W, (the valve opening into +the interior of the vessel), and the air will escape through the pipe +O P, which communicates, as we have explained, with the apertures of +the pipes G H K L and F M N X. When the globe is half full of liquid, +turn the small tube R S so as to break the connection between the +corresponding apertures: then depress the tube Y Z and drive out the +air and liquid collected in T U Q, which will, on the exertion of some +force, (as the vessel is full of air and liquid), pass through the +valve into the hollow of the globe; and this passage is made possible +by the compression of the air into the void spaces dispersed among its +particles. Draw up the tube Y Z, in order again to fill T U Q with +air, and then, depressing it again, we shall force this air into the +globe. By repeating this frequently we shall have a large quantity of +air compressed into the globe; for it is clear that the air forced in +does not escape again when the rod is drawn up, as the valve, pressed +on by the air within, remains closed. If, then, we restore the pipe R +S to its upright position, and re-open the communication between the +corresponding apertures at L and X, the liquid will now be forced out, +as the condensed air expands to its original bulk and presses on the +liquid beneath; and if the quantity of condensed air be large, it will +drive out all the liquid, and even the superfluous air will be forced +out at the same time. + + + + +10. _A Valve for a Pump._ + + +[Illustration: Diagram of apparatus as described in text] + +The following is the construction of the valve referred to. Take two +rectangular plates of bronze of the thickness of a carpenter’s rule, +and measuring about one finger’s breadth (⁷⁄₁₀ of an inch) on each +side. When these have been accurately fitted to each other, polish +their surfaces so that neither air nor liquid may pass between them. +Let A B C D, E F G H, (fig. 10) be the plates, and in the centre of one +of them, A B C D, bore a circular hole about ⅓ of a finger’s breadth (¼ +of an inch) in diameter. Then, applying the side C D to E F, let the +plates be attached by means of hinges, so that the polished surfaces +may come together. When the valve is to be used, fasten the plate A B +C D over the aperture, and any air or liquid forced through will be +effectually confined. For by the pressure exerted the hinges move, and +the plate E F G H opens readily to admit the air or liquid; which when +inclosed in the air-tight vessel, presses on the plate E F G H, and +closes the aperture through which the air was forced in. + + + + +11. _Libations at an Altar produced by Fire._ + + +[Illustration: Diagram of apparatus as described in text] + +To construct an altar such that, when a fire is raised on it, figures +at the side shall offer libations. Let there be a pedestal, A B C +D, (fig. 11) on which the figures stand, and also an altar, E F +G, perfectly air-tight. The pedestal must also be air-tight, and +communicate with the altar at G. Through the pedestal insert the tube H +K L, reaching nearly to the bottom at L, and communicating at H with a +bowl held by one of the figures. Pour liquid into the pedestal through +a hole, M, which must afterwards be closed. Now if a fire be lighted +on the altar E F G, the air within it, being rarefied, will descend +into the pedestal, and exert pressure on the liquid it contains, which, +having no other way of retreat, will pass through the tube H K L into +the bowl. Thus the figures will pour a libation, and will not cease so +long as the fire remains on the altar. When the fire is extinguished, +the libation ceases; and as often as the fire is kindled the same +will be repeated. The pipe through which the heat is to pass should +be broader towards the middle, for it is requisite that the heat, or +rather the vapour from it, passing into a broader space, should expand +and act with greater force. + + + + +12. _A Vessel from which the contents flow when filled to a certain +height._ + + +[Illustration: Diagram of apparatus as described in text] + +There are some vessels which emit no stream unless they are filled; but +when filled discharge all the liquid they contain. They are made as +follows: Let A B C D (fig. 12) be a vessel open at the top, and through +its bottom pass a tube, either an inclosed diabetes as E F G, or a bent +siphon G H K. When the vessel A B C D is filled, and the water runs +over, a discharge will begin through the diabetes, and continue till +the vessel is empty, if the interior opening of the diabetes is so near +the bottom of the vessel as only to leave a passage for the water. + + + + +13. _Two Vessels from which the contents flow, by a Liquid being poured +into one only._ + + +[Illustration: Diagram of apparatus as described in text] + +If two vessels, both of them having visible outlets, stand upon a +pedestal, and one of them be filled with wine, the other remaining +empty, the wine shall not flow out until the empty vessel be filled +with water; and then a discharge shall begin, of wine from one, and of +water from the other, until both are empty. Such vessels are called +_harmonious goblets_. Let A B C D (fig. 13) be the pedestal on which +the vessels, E and F, stand. In each of them place a bent siphon, G H K +in E, and L M N in F, and let the outer extremities of the siphons be +shaped like water-pipes. At the bend the siphons must approach nearly +to the mouths of the vessels. Let another bent tube, X O P R, passing +through the pedestal, connect the two vessels, the extremities of +which, X and R, must reach as high as the bend of the siphons. Now pour +wine into one vessel, taking care that it does not mount higher than +the bend of the siphon at H. Up to this point the wine will not flow +out, as there is nothing to originate a discharge through the siphon. +But if we pour water into the vessel F, until its surface mounts above +the bend of the siphon at M, then the water will descend and pass +through the pipe X O P R into the other vessel. Thus a discharge is +occasioned of the wine also, and both vessels will continue to run the +one with wine, the other with water, until both are emptied. + + + + +14. _A Bird made to whistle by flowing Water._ + + +[Illustration: Diagram of apparatus as described in text] + +Vessels may be made such that, when water is poured into them, the note +of the black-cap, or a whistling sound, is produced. The following +is their construction. Let A B C D (fig. 14) be a hollow air-tight +pedestal: through the top, A D, let a funnel, E F, be introduced and +soldered into the surface, its tube approaching so near to the bottom +as only to leave a passage for the water. Let G H K be a small pipe, +such as will emit sound, communicating with the pedestal and likewise +soldered into A D. Its extremity, which is curved, must dip into water +contained in a small vessel placed near at L. If water be poured in +through the funnel E F, the result will be that the air, being driven +out, passes through the pipe G H K, and emits a sound. When the +extremity of the pipe dips into water a bubbling sound is heard, and +the note of the black-cap is produced: if no water is near, there will +be a whistling only. + +These sounds are produced through pipes; but the quality of the sounds +will vary as the pipes are more or less fine, or longer, or shorter; +and as a larger or smaller portion of the pipe is immersed in the +water: so that by this means the distinct notes of many birds can be +produced. The figures of several different birds are arranged near a +fountain, or in a cave, or in any place where there is running water: +near them sits an owl, which, apparently of her own accord, turns at +one time towards the birds, and then again away from them; and when the +owl looks away the birds sing, when she looks at them they are mute: +and this may be repeated frequently. + + + + +15. _Birds made to sing, and be silent alternately by flowing Water._ + + +The construction is after this manner. Let A (fig. 15) be a stream +perpetually running. Underneath place an air-tight vessel, B C D E, +provided with an inclosed diabetes or bent siphon F G, and having +inserted in it a funnel, H K, between the extremity of the tube of +which and the bottom of the vessel a passage is left for the water. Let +the funnel be provided with several smaller pipes, as described before, +at L. It will be found that, while B C D E is being filled with water, +the air that is driven out will produce the notes of birds; and as the +water is being drawn off through the siphon F G after the vessel is +filled, the birds will be mute. + +[Illustration: Diagram of apparatus as described in text] + +We are now to describe the contrivance by which the owl is enabled to +turn herself towards, or away from, the birds, as we have said. Let a +rod N X turned in a lathe rest on any support M: round this rod let a +tube O P be fitted, so as to move freely about it, and having attached +to it the kettle-drum top R S, on which the owl is to be securely +fixed. Round the tube O P let a chain pass, the two extremities of +which, T U, Q W, wind off in opposite directions, and are attached, by +means of two pullies, the one, T U, to a weight suspended at Y, and +Q W to an empty vessel Z, which lies beneath the siphon or inclosed +diabetes F G. It will be found that while the vessel B C D E is being +emptied, the liquid being carried into the vessel Z causes the tube O +P to revolve, and the owl with it, so as to face the birds: but when +B C D E is exhausted, the vessel Z becomes empty likewise by means of +an inclosed or bent siphon contained within it; and then the weight Y, +again preponderating, causes the owl to turn away just at the time when +the vessel B C D E is being filled again and the notes once more issue +from the birds. + + + + +16. _Trumpets sounded by flowing Water._ + + +In the same manner as that just described the sound of trumpets can be +produced. Insert into a carefully closed vessel the tube of a funnel +reaching nearly to the bottom and soldered into the surface of the +vessel; and, by its side, a trumpet, provided both with a mouthpiece +and bell, and communicating at its upper extremity with the vessel. +If water be poured through the funnel, it will be found that the +air contained in the vessel, as it is being driven out through the +mouthpiece, will produce the sound of a trumpet. + + + + +17. _Sounds produced on the opening of a Temple Door._ + + +[Illustration: Diagram of apparatus as described in text] + +The sound of a trumpet may be produced on the opening of the doors +of a temple. The following is the construction. Behind the door let +there be a vessel, A B C D (fig. 17), containing water. In this invert +a narrow-necked vessel, shaped like an extinguisher, F, with which, +at its lower extremity, let a trumpet, H K, communicate, provided +with bell and mouthpiece. Parallel with the tube of the trumpet, and +attached to it, let the rod L M run, fastened, at the lower end, to +the vessel F, and having at the other extremity a loop, M: through +this loop let the beam N X pass, thus supporting the vessel F, at a +sufficient height above the water. The beam N X must turn on the pivot +O, and a chain or cord, attached to the extremity X, be fastened, by +means of the pulley, P, to the hinder part of the door. When the door +is opened, the cord will be stretched, and draw upwards the extremity +X of the beam, so that the beam N X no longer supports the loop M; and +when the loop changes its position in consequence, the vessel F will +descend into the water, and give forth the sound of a trumpet by the +expulsion of the air contained in it through the mouthpiece and bell. + + + + +18. _Drinking-Horn from which either Wine or Water will flow._ + + +[Illustration: Diagram of apparatus as described in text] + +There is a kind of drinking-horn, such that if wine be first poured +into it, and then water, sometimes the water flows out unmixed, and +sometimes the wine. The following is the construction. Let A B C +(fig. 18) be a drinking-horn, furnished with two partitions, D E and +F G: through both of these let a tube, H K, pass, soldered into the +partitions, and pierced with a small hole, L, situated a little above +the partition F G; and under the partition D E let there be a vent, M, +in the side of the vessel. If, when these arrangements are complete, +we close the passage at C and pour in wine, it will pass through the +vent M; and, if we cover M with the finger, the wine in D E F G will +be retained. Now, if we pour [water] into the part A B D E, still +closing the vent M, pure water will flow out; but if, while the water +is still in the upper part of the vessel, we unclose M, a mixture will +be discharged; and when all the water has passed out, the stream will +be of pure wine. By frequently unclosing M the discharge may be varied: +but the better method is first to pour water into the chamber D E G F, +and then, closing the vent, to pour wine upon it. The result will be +that sometimes pure water flows out, and again, when the siphon is set +free, a mixture; presently, on stopping the vent, pure wine. And this +can be done as often as we please. + + + + +19. _A Vessel containing a Liquid of uniform height, although a Stream +flows from it._ + + +[Illustration: Diagram of apparatus as described in text] + +If a goblet be placed upon a pedestal, whatever quantity may be drawn +from it, it shall always continue full. The construction is as follows. +Let A B (fig. 19) be a vessel, the mouth of which is closed just at the +neck, by the partition C D. Through C D let a tube, E F, be inserted, +reaching nearly to the bottom; let another tube, G H, be passed through +the bottom of the vessel, reaching nearly up to the partition C D; and +in the bottom bore a hole, K, to admit the small tube K L. The vessel +A B must stand upon a pedestal, M N O X, through which passes the +projection of the tube G H, and another tube S T communicating with the +pedestal and the goblet P R so that the goblet may be filled, and the +pedestal M N O X as high, &c. Now let wine be poured through E F into +A B (the air will pass out through G H), and, if the tube K L be left +open, it will pass through into the pedestal and the goblet P R: but, +if K L be closed, the vessel A B will be filled. Let, then, the wine +run into the pedestal M N O X and the goblet P R, so that the goblet may +be filled, and the pedestal M N O X as high as the mouth of the tube +G H. When this is done, close E, and the wine in A B will no longer +[flow] through K L, for no more air can enter through E to supply the +vacuum created. When, therefore, any wine is taken from the goblet, the +orifice E must be unclosed, and, the air having found an entrance, the +wine will flow again into the pedestal and goblet, until it is full. +And this may be done as often as we draw off wine from the goblet. +It will be requisite that a small hole be pierced in the side of the +pedestal at U, that an equivalent bulk of air may pass into the vessel +A B through the orifice G and the hole U. + + + + +20. _A Vessel which remains full, although Water be drawn from it._ + + +[Illustration: Diagram of apparatus as described in text] + +If it is desired to adapt this contrivance for use, so that from a +goblet occupying any given position a considerable quantity of water +may be drawn and yet the goblet remain full, proceed as follows. Let A +B (fig. 20) be a vessel containing as much water as will probably be +required, and C D a pipe leading from this into a trough beneath, G H. +Near the pipe fix a lever-beam, E F, and at the extremity E suspend +a piece of cork, K, so that it may float in the trough; at the other +extremity F let a chain be fastened furnished with a leaden weight, X. +Let the whole be so arranged that the cork, floating on the water in G +H, closes the mouth of the pipe; yet that, when water has been drawn +from the trough, the cork, being heavier than the weight at X, shall +sink and open the pipe, so that the water may flow in again and raise +the cork. Let L M be the goblet placed in any convenient position, its +lip being on a level with the surface of the water in the trough when +there is no discharge from the pipe owing to the floating cork: and let +the tube H N lead from the trough into the bottom of the goblet. Now +if, when the goblet is full, we draw water from it, we shall at the +same time reduce the water in the trough; and the cork sinking will +unclose the pipe, so that the water, flowing both into the trough and +the goblet, will again raise the cork, and the discharge will cease. +And this will happen as often as we remove water from the goblet. + + + + +21. _Sacrificial Vessel which flows only when Money is introduced._ + + +[Illustration: Diagram of apparatus as described in text] + +If into certain sacrificial vessels a coin of five drachms be thrown, +water shall flow out and surround them. Let A B C D (fig. 21) be a +sacrificial vessel or treasure chest, having an opening in its mouth, +A; and in the chest let there be a vessel, F G H K, containing water, +and a small box, L, from which a pipe, L M, conducts out of the chest. +Near the vessel place a vertical rod, N X, about which turns a lever, O +P, widening at O into the plate R parallel to the bottom of the vessel, +while at the extremity P is suspended a lid, S, which fits into the box +L, so that no water can flow through the tube L M: this lid, however, +must be heavier than the plate R, but lighter than the plate and coin +combined. When the coin is thrown through the mouth A, it will fall +upon the plate R and, preponderating, it will turn the beam O P, and +raise the lid of the box so that the water will flow: but if the coin +falls off, the lid will descend and close the box so that the discharge +ceases. + + + + +22. _A Vessel from which a variety of Liquids may be made to flow +through one Pipe._ + + +[Illustration: Diagram of apparatus as described in text] + +Several kinds of liquid having been poured into a vessel through one +mouth, it is required that through the same pipe they shall flow out +separately at pleasure. Let A B (fig. 22) be a vessel closed at the +neck by the partition C D; and let there be in it several vertical +partitions, extending to the partition C D and making as many chambers +as we wish to pour in liquids. Suppose, for the present, that these +are two in number, and let the partition be E F. In the partition C D +pierce fine holes, as in a sieve, opening into each chamber, and air +holes, G, H, close to the partition, also opening into the chambers: +again, at the bottom let there be small tubes, K, L, communicating +with the chambers and opening into the common pipe M. If, having first +closed the vents G, H, and the pipe M, we pour one of the liquids +through the mouth of the vessel, it will enter into neither chamber, as +the air has no means of escape: but if one of the vents be opened, the +liquid will pass into that chamber to which the vent belongs; and if, +after closing this vent again, we pour in the other liquid and set free +the other vent, the liquid will pass into the other chamber. Now let +all the vents and the sieve-like holes be closed, and, on opening the +pipe M, no discharge can take place until one of the vents be opened; +when, the air having found an entrance, the liquid contained in that +chamber will flow out. If this vent be closed and the other opened, the +same result will follow. + + + + +23. _A Flow of Wine from one Vessel, produced by Water being poured +into another._ + + +[Illustration: Diagram of apparatus as described in text] + +If of two vessels standing on a pedestal one be full of wine and the +other empty, whatever quantity of water be poured into the empty +vessel, as much wine shall flow from the other. The following is the +construction. On any pedestal, A B (fig. 23) let there be two vessels, +C D, E F, having their mouths closed by the partitions G H, K L. Let +the tube M N X O pass through the pedestal and bend upwards into the +vessels, reaching very nearly to the partitions at M and O. In E F +place a bent siphon, P R S, the bend being near the vessel’s mouth, +and one leg, shaped like a water-pipe, passing outside. Through the +partition G H let a funnel, T U, descend almost to the bottom of the +vessel, its tube being soldered into the partition. Into the vessel E F +pour wine through a hole, Q, which must afterwards be carefully closed +again. Now, if we pour water into the vessel C D through the funnel, +the contained air will be forced out, and pass through the tube M N X +O into E F, and, in its turn, force out the wine contained in E F: and +this will happen as often as we pour in the water. It is evident that +the air forced out has an equal bulk with the water poured in, and that +it will force out as much wine. If no bent siphon be used, but merely a +pipe at S, the effect will be the same, unless the force of the water +be too great for the pipe. + + + + +24. _A Pipe from which flows Wine-and-Water in varying proportions._ + + +[Illustration: Diagram of apparatus as described in text] + +Let there be an empty vessel, and another containing wine: whatever +quantity of water we pour into the empty vessel, the same quantity of +wine and water mixed may be drawn off through a pipe in any proportion +we please; such, for instance, that there may be two parts of water to +one of wine. Let A B (fig. 24) be an empty vessel, either a cylinder +or a rectangular parallelopiped: by the side of this, and on the same +base, place another vessel, C D, perfectly air-tight, and, like A B, +either a cylinder or a rectangular parallelopiped; but the base of A B +must be twice as great as that of C D, as the water is to be the double +of the wine. Near C D place another air-tight vessel, E F, into which +the wine is to be poured; and between the vessels C D, E F, let a tube +run, G H K, perforating and soldered into their coverings. In E F let +there be a bent siphon, L M N, the inner leg of which must reach almost +to the bottom of the vessel, leaving only a passage for the water, and +the other, being bent within the vessel, lead into the next vessel, O +X. From this vessel let the tube P R lead through the vessels, or be +carried under the pedestal on which they stand, that it may readily +pass near the bottom of the vessel A B. Let another tube, T S, connect +the vessels A B, C D, and near the bottom of A B place a small pipe, U, +which with P R must be included in a larger pipe, Q W, provided with a +cock by means of which it may be opened or shut at pleasure. When these +preparations have been made, close the pipe Q W, and pour water into +the vessel A B; a part, viz. one half, will pass into C D, through the +tube S T, and the water which falls into C D will force out a mass of +air equal to itself through G H K into the vessel E F; in like manner +this air will force an equal quantity of wine into the vessel O X +through L M N. Now, if we open the pipe Q W, the water poured into the +vessel A B and the wine carried out of O X through the tube P R will +flow through it together: and thus what was proposed will be done. The +vessels will be empty again when, the mixed liquid having been all +discharged, the air enters them through the tube P R. + + + + +25. _A Vessel from which Wine flows in proportion as Water is +withdrawn._ + + +[Illustration: Diagram of apparatus as described in text] + +Let there be a vessel containing water, and a pipe in it provided with +a key or cock, and let a figure float on the surface of the water; then +if water, in any quantity, be drawn off through the pipe, wine shall +flow from the figure in any given ratio to the water drawn off. Let +A B (fig. 25) be the vessel of water, provided with a pipe, C, which +admits of being closed; and on the surface of the water let a basin, +D, float, in which is a perpendicular tube, E F, carved in the shape of +some animal. Place near another vessel, G H, containing wine, in which +is a bent siphon, K L M, one leg being within the vessel G H, and the +other without, conducting into the tube E F. Now if we draw the wine +through the lower mouth M, it will flow into the tube E F until the +surface of the wine in the vessel G H and in the tube E F shall be at +the same level. Let that level be in the line N X O P; and at the point +P fix an open pipe, R. Hitherto there is no discharge of wine, but, if +any quantity of water is drawn off through C, the basin D, and, with +it, the tube E F will sink, and the surface of the wine [in the tube] +will become lower than the surface N X; so that, the outer leg of the +siphon being depressed, the wine will again pass on into the tube E F +and run out through the pipe R. This will happen as often as we draw +off water through the pipe C, the wine flowing in a fixed ratio to the +water drawn off. The base of the vessel A B must bear the required +proportion to the base of G H; and thus what was proposed is done. + + + + +26. _A Vessel from which Wine flows in proportion as Water is poured +into another._ + + +If it is required that the wine shall flow in a certain ratio to the +water we pour _into_ the vessel, we must proceed as follows. As before +let A B (fig. 26) be the vessel containing water, and G H that which +contains wine, but let the tube E F be outside the vessel A B. In A +B let a ball, D, float, from which a cord, passing over a pulley, S, +is attached to the tube E F so as to suspend it; and let all else +correspond with what was stated in the last paragraph. The result will +be that, when water is poured into the vessel A B, the ball D rising +will lower the tube E F, and the wine will flow again. This may be +effected in a different manner by attaching the cord from the ball D, +across the pulley S to another pulley, T and across that again to the +siphon K L. It will be found now that, when the ball rises, the siphon +K L M, being suspended by the cord, is lowered, so that, the outer leg +having again become the longer, the wine will flow through the mouth M. + +[Illustration: Diagram of apparatus as described in text] + + + + +27. _The Fire-Engine._ + + +[Illustration: Diagram of apparatus as described in text] + +The siphons used in conflagrations are made as follows. Take two +vessels of bronze, A B C D, E F G H, (fig. 27), having the inner +surface bored in a lathe to fit a piston, (like the barrels of +water-organs), K L, M N being the pistons fitted to the boxes. Let +the cylinders communicate with each other by means of the tube X O +D F, and be provided with valves, P, R, such as have been +explained above, within the tube X O D F and opening outwards from the +cylinders. In the bases of the cylinders pierce circular apertures, +S, T, covered with polished hemispherical cups, V Q, W Y, through +which insert spindles soldered to, or in some way connected with, the +bases of the cylinders, and provided with shoulders at the extremities +that the cups may not be forced off the spindles. To the centre of +the pistons fasten the vertical rods S E, S E, and attach to these +the beam A´ A´, working, at its centre, about the stationary +pin D, and about the pins B, C, at the rods S E, S E. Let +the vertical tube S´ E´ communicate with the tube X O D F, branching +into two arms at S´, and provided with small pipes through which to +force up water, such as were explained above in the description of +the machine for producing a water-jet by means of the compressed air. +Now, if the cylinders, provided with these additions, be plunged into +a vessel containing water, I J U Z, and the beam A´ A´ be made to work +at its extremities A´, A´, which move alternately about the pin D, the +pistons, as they descend, will drive out the water through the tube +E´ S´ and the revolving mouth M´. For when the piston M N ascends it +opens the aperture T, as the cup W Y rises, and shuts the valve R; but +when it descends it shuts T and opens R, through which the water is +driven and forced upwards. The action of the other piston, K L, is the +same. Now the small pipe M´, which waves backward and forward, ejects +the water to the required height but not in the required direction, +unless the whole machine be turned round; which on urgent occasions is +a tedious and difficult process. In order, therefore, that the water +may be ejected to the spot required, let the tube E´ S´ consist of +two tubes, fitting closely together lengthwise, of which one must be +attached to the tube X O D F, and the other to the part from which the +arms branch off at S´; and thus, if the upper tube be turned round, +by the inclination of the mouthpiece M´ the stream of water can be +forced to any spot we please. The upper joint of the double tube must +be secured to the lower, to prevent its being forced from the machine +by the violence of the water. This may be effected by holdfasts in the +shape of the letter L, soldered to the upper tube, and sliding on a +ring which encircles the lower. + + + + +28. _An Automaton which drinks at certain times only, on a Liquid being +presented to it._ + + +[Illustration: Diagram of apparatus as described in text] + +In any place provided with running water make a figure of some animal +in bronze or any other material: when a cup is offered to it, the +animal shall drink with a loud noise so as to present the appearance of +thirst. The following is the construction. A B (fig. 28) is a vessel +into which a stream of running water, C, falls. In A B place a bent +siphon or inclosed diabetes, D E F, one leg of which must project below +the bottom of the vessel. Underneath this let there be an air-tight +pedestal, G H K L, also containing a bent siphon, M N X. Below the +orifice F place a funnel, O P, the tube of which must descend into the +pedestal leaving a passage for the water between its extremity and the +bottom. Let the mouth of the animal be at R, from which a concealed +tube, R S T, must run along one of the feet, or some other part, into +the pedestal. When the vessel A B is filled, the water will overflow +and run into the funnel, filling the pedestal G H K L and emptying +the vessel A B; in like manner, when the pedestal is full, the water +will overflow through the siphon M N X and empty the pedestal; and, as +this becomes empty, the air will enter through the mouth R to fill up +the void that is left. If, then, we apply a drinking vessel at R, the +liquid will be violently attracted and sucked down instead of the air, +until the pedestal within has become empty. Then the vessel A B is +again filled and emptied, and the same will take place as before. In +order that the cup may be applied at the right time, that is, when the +water is being drawn off from the pedestal, let something be contrived +that will move when struck by water from the discharge through the +siphon M N X. When this is seen to move, apply the drinking cup. + + + + +29. _An Automaton which may be made to drink at any time, on a Liquid +being presented to it._ + + +[Illustration: Diagram of apparatus as described in text] + +There is another way in which, by the aid of running water, the animal +may be made to drink on the revolution of a carved figure of Pan. Let +A B C D (fig. 29) be a pedestal, air-tight on every side, and divided +into two chambers by a partition. On the surface place the animal, and +let the tube E F G pass through its mouth. Within the pedestal, in +the lower chamber, let there be a bent siphon, H K L, the lower leg +projecting from the bottom: and let a funnel, M N, pass through the +middle of the partition, its tube reaching nearly to the bottom. On the +pedestal A B C D place another pedestal, O X, on which the figure of +Pan, P R, is to stand, having attached to it the rod S which projects +below into the pedestal. To S let the tube T U be fastened, at the end +of which is the cup U Q, attached to and communicating with the tube. +Let the tube be of such a length that, when the figure P R turns round, +the cup U Q will be directly above the funnel M N. On the pedestal, and +communicating with it, and directly above the funnel M N, place the +cup W Y. Let the stream Z, (which must be greater than the discharge +through the siphon H K L), flow into W Y: the liquid will pass through +M N into the lower part of the pedestal, the contained air passing out +through E F G: and now the pedestal will continue full as the influx is +greater than the discharge. But, when we turn the figure P R round, the +cup U Q will intercept the stream Z, which will pass elsewhere through +the tube T U, and, as the water no longer flows into the lower chamber +of the pedestal, the siphon H K L will empty it, and the air will enter +through E F G. Thus, when the cup is applied, the animal will drink as +before. + + + + +30. _An Automaton which will drink any quantity that may be presented +to it._ + + +[Illustration: Diagram of apparatus as described in text] + +The animal may be made to drink without the aid of running water, +or of any thing to move the figure of Pan. Let A B C D (fig. 30) be +a pedestal, and E the mouth of the animal, through the breast and +hinder foot or tail of which a tube, E F G, is inserted, leading from +the mouth E to the interior of the pedestal. The pedestal having +been first firmly fixed, let a hole, E, so fine as to be scarcely +discernible, be bored in the tube E F G which passes through the +animal, in a line with the extremity G. Now if we fill the siphon E F G +with water through some pipe above it, the mouth of which is applied to +E, the siphon will continue full since its two orifices lie in the same +level. If, therefore, a drinking vessel be brought to the mouth E, and +a portion of the mouth immersed in it, it will be found that the leg of +the siphon towards G has become the longer, so that it will attract the +water, and the water attracted is carried into the pedestal A B C D. In +this construction it is not necessary that A B C D should be air-tight. + + + + +31. _A Wheel in a Temple, which, on being turned, liberates purifying +Water._ + + +In the porticoes of Egyptian temples revolving wheels of bronze are +placed for those who enter to turn round, from an opinion that bronze +purifies. There are also vessels of lustral water, from which the +worshippers may sprinkle themselves. Let it then be required so to +construct a wheel that, on turning it round, water shall flow from +it to sprinkle the worshippers as we have described. Behind the +entrance-pillar let a vessel of water, A B C D (fig. 31), be concealed, +having a hole, E, perforated in its base. Underneath the base let a +small tube, F G H K, be fastened, having also a hole bored opposite the +orifice in the base, and within this place another tube, L M, soldered +to the tube F G H K at L, and opposite the orifice having in like +manner a hole, S: between these two pipes let another pipe, N X O R, +be closely fitted, with a hole at P opposite to E. Now, if the several +holes are in one line, when water is poured into the vessel A B C D it +will flow out through the pipe L M; but, if the pipe N X O R is made to +revolve so as to change the position of the hole P, the discharge will +cease. Attach the wheel to the pipe N X O R, and, if it is repeatedly +made to revolve, water will flow out. + + + + +32. _A Vessel containing different Wines, any one of which may be +liberated by placing a certain Weight in a Cup._ + + +If several kinds of wine be poured into a vessel by its mouth, any one +of them at choice may be drawn out through the same pipe: so that, +if several persons have poured in the several wines, each one may +receive his own according to the proportion poured in by him. Let A +B C D (fig. 32), be an air-tight vessel, the neck of which is closed +by a partition, E F; and let the whole vessel be divided into as many +compartments as we intend there shall be different kinds of wine. +Suppose, for instance, that G H, K L, are the partitions, making three +compartments, M, N, and X, into which the wine will be poured. In the +partition E F pierce small holes, one in each compartment, O, P, R; and +from these holes let small tubes, P S, O T, R U, communicating with the +vessel, extend up into the neck. Perforate the partition E F, near +each tube, with fine sieve-like holes, through which the liquid will +pass into the compartments. When it is desired to pour in each kind of +wine, place the fingers on S, T, and U, and pour in the wine through +the neck Q; it will not pass into either of the compartments as the air +contained in them has no outlet. But, if we set free one of the vents +S, T, or U, the air contained in the corresponding compartment will +pass out through the passage as the wine falls into the compartment. +Then, placing the finger again on this vent, set another free in like +manner, and pour in another kind of wine: and so in order with the +rest, as many as there may be both of compartments and kinds of wine. +We may procure each wine, in its due quantity, through the same pipe in +the following manner. In the base of the vessel A B C D let there be +tubes leading from each compartment, W Y from M, Z A´ from N, and B´ C´ +from X: the extremities of these tubes Y, A´ and C´, must communicate +with another tube Y A´ C´, into which another tube, E´ F´, is tightly +fitted, closed at the interior extremity F´, and having holes pierced +in it opposite to Y, A´, and C´ so that, as the tube E´ F´ revolves, +when the holes pierced in it coincide consecutively with the holes Y, +A´, and C´, they may admit the wine contained in each chamber and send +it forth through the outer mouth of the tube E´ F´. To the tube E´ F´ +attach an iron rod, G´ H´; to this, at the extremity H´, solder a mass +of lead, K´, and at G´ an iron pin, L´ M´, to the middle of which is +fastened a cup, L, with the concavity upwards: let the interior of this +be a hollow truncated cone of which M´ is the larger circle and N´ the +less, and through this the pin L´ M´ is to pass. Take several balls +of lead, varying in weight, and equal in number to the compartments +M, N, X; and if we place the least of the balls in the cup M´ N´, it +will descend by its weight until it touches the hollow surface of the +truncated cone, causing the tube E´ F´ to revolve until the hole in it +coincides with Y and admits the wine in the compartment M, which will +flow as long as the ball remains in the cup, unless it be entirely +exhausted: when we remove the ball the weight K´ will turn back and +close the orifice Y, and the discharge will cease. Again, insert +another of the balls, and the cup will descend lower and turn the +tube E´ F´ further round until the hole in it reaches the hole A´, and +then the wine in N will flow: as before when the ball is removed the +weight K´ will run down and close the orifice A´, and the wine will +cease to flow. If another ball still heavier be placed in the cup, the +tube E´ F´ will be turned still further round, so that the wine in the +compartment X will flow. It is necessary however that the least of the +balls when placed in the cup should preponderate over the weight K´, +or, in other words, be able to cause E´ F´ to revolve; for then the +other balls will preponderate and move E´ F´. + + + + +33. _A self-trimming Lamp._ + + +[Illustration: Diagram of apparatus as described in text] + +To contrive a self-trimming lamp. Let A B C (fig. 33), be a lamp +through the mouth of which is inserted an iron bar, D E, capable of +sliding freely about the point E, and let the wick be wound loosely +about the bar. Place near a toothed wheel F, moving freely about an +axis, its teeth in contact with the iron bar, that, as the wheel +revolves, the wick may be pushed on by means of the teeth. Let the +opening for the oil be of considerable width, and when the oil is +poured in let a small basin float upon it, G, to which is attached a +perpendicular toothed bar, H, the teeth of which fit into the teeth of +the wheel. It will be found that, as the oil is consumed, the basin +sinks and causes the wheel F to revolve by means of the teeth of the +bar, and thus the wick is pushed on. + + + + +34. _A Vessel from which Liquid may be made to flow, on any portion of +Water being poured into it._ + + +[Illustration: Diagram of apparatus as described in text] + +If into a vessel, provided at the bottom with an open spout, liquid is +poured, the spout shall sometimes run from the first, sometimes when +the vessel is half filled, and sometimes not until the whole is filled: +in fine, when any proposed quantity of liquid has been poured in, the +spout shall run until all is exhausted. Let A B (fig. 34), be the +vessel, the neck of which is closed: insert the tube C D, air-tight, +through the partition, and let it reach to the bottom of the vessel +leaving only a passage for the water. Let E F G be a bent siphon, +the inner leg of which extends nearly to the bottom of the vessel, +while the other projects without, being fashioned in the shape of a +water-spout: the curve of the siphon must be close to the neck of the +vessel. In A B make an air-hole, H, near the partition and leading into +the body of the vessel. If we intend the spout to run immediately on +the entrance of the liquid, we must place the finger on the vent H, and +the spout will run, for as the air in the vessel has no way of retreat, +the liquid will rush out through the bent siphon. If we do not close H, +the liquid will pass into the body of the vessel, and the spout cannot +run until we again close the vent: and then, if we set the vent free, +the siphon will exhaust all the liquid. + + + + +35. _A Vessel which will hold a certain quantity of Liquid when the +supply is continuous, will only receive a portion of such Liquid if the +supply is intermittent._ + + +A vessel can be made which, as long as you pour in any liquid, admits +it, but, if you once cease pouring, holds no more: the construction is +in this manner. Let A B (fig. 35), be a vessel, the neck of which is +closed by the partition C D. Through the partition insert the tube E F, +reaching nearly to the bottom, and projecting above the partition so as +almost to reach the brim of the vessel; and let this tube be encircled +by another G H, the top of which is closed by a lid, at a sufficient +interval from the partition and the tube E F to admit of the passage +of water: in A B make an air-hole, K, leading into the body of the +vessel. Now, if we pour liquid into the vessel’s neck, it will be found +that it will pass into the body through the tubes G H and E F, the +air retreating through the vent K. But, if we cease pouring, and the +neck of the vessel becomes empty, the air will break the continuity, +so that any liquid in G H will flow down and fall upon the partition; +for the breadth about the tube G H should be considerable, that the +water may fall by its own weight. If more liquid be poured in, the air +confined in the tubes E F and G H will not allow it to pass through, so +that it will run over the brim of the vessel. + + + + +36. _A Satyr pouring Water from a Wine-skin into a full Washing-Basin, +without making the contents overflow._ + + +[Illustration: Diagram of apparatus as described in text] + +Construct on a pedestal the figure of a satyr holding in his hands a +wine-skin: place near a washing-basin, and into this let some liquid +be poured until it is full; water shall be made to flow into the basin +without running over, until all the water in the skin is exhausted. +The following is the construction. Let A B (fig. 36), be a perfectly +air-tight pedestal, either cylindrical or octagonal in shape, as may +seem more elegant, and divided into two chambers by the partition C D, +through which the tube E F, fitting closely into the partition, extends +upwards nearly to the roof of the pedestal. Through the roof insert +the tube G H, projecting slightly above the vessel, and lying exactly +under the basin, while, below, it reaches to the bottom except that +room must be left for the passage of water: this tube must be soldered +into the roof of the pedestal and the partition. Another tube, K L M, +must also be inserted through the roof, reaching not quite so low as +the partition, soldered into the roof and carrying its stream into the +basin, which lies above the tube G H and communicates with it. Now let +the vessel A D be filled with water through an orifice N, which must +be afterwards closed. If water is poured into the basin, it will pass +through the tube G H into the vessel B C; and the air in B C, passing +through the tube E F and into the vessel A D, will force the liquid in +A D through K L M into the basin; and this being carried again into B +C will force out the contained air as before, which, again, will force +the water in the vessel A D into the basin: and this will go on until +the water in A D is exhausted. The tube K L M must pass through the +mouth of the skin and be particularly fine, that the display may last a +considerable time. + + + + +37. _Temple Doors opened by Fire on an Altar._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a small temple such that, on lighting a fire, +the doors shall open spontaneously, and shut again when the fire is +extinguished. Let the proposed temple stand on a pedestal, A B C D +(fig. 37), on which lies a small altar, E D. Through the altar insert a +tube, F G, of which the mouth F is within the altar, and the mouth G is +contained in a globe, H, reaching nearly to its centre: the tube must +be soldered into the globe, in which a bent siphon, K L M, is placed. +Let the hinges of the doors be extended downwards and turn freely on +pivots in the base A B C D; and from the hinges let two chains, running +into one, be attached, by means of a pulley, to a hollow vessel, N X, +which is suspended; while other chains, wound upon the hinges in an +opposite direction to the former, and running into one, are attached, +by means of a pulley, to a leaden weight, on the descent of which the +doors will be shut. Let the outer leg of the siphon K L M lead into the +suspended vessel; and through a hole, P, which must be carefully closed +afterwards, pour water into the globe enough to fill one half of it. It +will be found that, when the fire has grown hot, the air in the altar +becoming heated expands into a larger space; and, passing through the +tube F G into the globe, it will drive out the liquid contained there +through the siphon K L M into the suspended vessel, which, descending +with its weight, will tighten the chains and open the doors. Again, +when the fire is extinguished, the rarefied air will escape through the +pores in the side of the globe, and the bent siphon, (the extremity of +which will be immersed in the water in the suspended vessel) will draw +up the liquid in the vessel in order to fill up the void left by the +particles removed. When the vessel is lightened the weight suspended +will preponderate and shut the doors. Some in place of water use +quicksilver, as it is heavier than water and is easily disunited by +fire. + + + + +38. _Other intermediate means of opening Temple Doors by Fire on an +Altar._ + + +[Illustration: Diagram of apparatus as described in text] + +There is another way in which, on lighting a fire, the doors will open. +As before, let a small temple stand upon a base, A B C D (fig. 38), on +which is an altar, E. Let a tube, F G H, pass through the altar and +be attached to a leathern bag, K, perfectly air-tight: beneath this +let a small weight, L, hang, from which a chain is attached across a +pulley to the chains round the hinges, so that, when the bag is folded +together, the weight L preponderates and shuts the doors, and when fire +is placed on the altar they are opened. For, as before, the air in the +altar growing hot, and expanding, will pass through the tube F G H into +the bag, and raise it up with the weight L; and then the doors will be +opened. The doors will either open of themselves, as the doors of baths +shut spontaneously, or they may have a counterbalancing weight to open +them. When the sacrifice is extinguished, and the air which has entered +the bag passes out, the weight, descending with the bag, will tighten +the chains and close the doors. + + + + +39. _Wine flowing from a Vessel may be arrested on the Introduction of +Water, but, when the Supply of Water ceases, the Wine flows again._ + + +[Illustration: Diagram of apparatus as described in text] + +If there be a vessel containing wine, and provided with three spouts, +wine shall flow through the middle of the three; and, when water is +poured in, the stream of wine shall cease, and water shall flow through +the other two; again, when the stream of water ceases, wine shall flow +through the middle spout: and this shall take place as often as we pour +in water. Let A B (fig. 39), be a vessel, the neck of which is closed +by the partition C D, and having a spout, E, at the bottom. Let two +tubes, F G H, K L M, terminating in spouts, pass through the partition +and project above it; and round the projecting parts place other tubes, +N, X, covered with lids at the top and extending to the partition +except a passage for the water. Another tube, P, reaching nearly up to +the partition, communicates with F G H. Having first closed the spout +E, fill the vessel A B with wine through an orifice, Q, which must +be carefully closed afterwards. When E is set free it will be found +that wine flows through it, for air enters from without into the void +created, through the orifice H and the tube P. Now, if we pour water +upon the partition C D, it will be carried out through the tubes F G +H, K L M; but, as the air has no means of entering the vessel A B, +the wine will cease to flow until all the water has escaped, when the +air finds an entrance again and the wine flows. Instead of the tube +P, another tube, R S, may be used, piercing through the partition, +about which another, T U, must lie, like the tubes N and X, but higher +than those, so that R S may rise above the lip of the vessel. The same +result will follow. + + + + +40. _On an Apple being lifted, Hercules shoots a Dragon which then +hisses._ + + +[Illustration: Diagram of apparatus as described in text] + +On a pedestal is placed a small tree round which a serpent or dragon +is coiled; a figure of Hercules stands near shooting from a bow, and +an apple lies upon the pedestal: if any one raises, with the hand, +the apple a little from the pedestal, Hercules shall discharge his +arrow at the serpent and the serpent hiss. Let A B (fig. 40) be the +proposed pedestal, air-tight and divided by a partition, C D. Fixed in +the partition is a hollow truncated cone, E F, the lesser circle of +which, F, is open and approaches to the bottom of the pedestal, leaving +a sufficient interval for the passage of water. To this cone must be +tightly fitted another cone H, attached by means of a chain through a +hole in the surface, to the apple K, which lies on the pedestal. Let +Hercules hold a small bow of horn, the string of which is stretched, +and at the proper distance from the hand. In the right hand, and +directed towards the serpent, let there be a hand in every respect +similar to the visible hand, but smaller, and holding the trigger. From +the extremity of the trigger let a chain, or cord, proceed through +the pedestal and be attached to a pulley, which is placed above the +partition, and again to the chain which is connected with the cone +and apple. Now we must draw the bow, and placing the trigger beneath +the hand, close it so that the cord is stretched and draws the apple +tightly downwards: the cord must run inside Hercules and through the +body and hand. From the partition let a small tube, one of those which +are used to whistle, extend above the pedestal and pass under the tree +or along its trunk. Then fill the vessel A D with water. Let L M be the +tree, N X the bow, S P the string, R S the hand that grasps the bow, T +U the trigger, Q W the cord, W the pulley round which the cord runs, +and Y Z the whistling pipe. Now if some one raise the apple K, he will +at the same time raise the cone H, tighten the cord Q W, and draw back +the hand, so that the arrow is discharged: and the water in A D, being +carried into B C, will drive out the air contained in B C through the +pipe, and produce the hissing sound. When the apple is replaced, the +cone H fitting again into the other, will stop the stream of water so +that no sound is produced. We must now re-arrange the arrow and leave +it. If the vessel B C is full, it can be emptied again by means of a +spout with a key: A D must be filled as before. + + + + +41. _A Vessel from which uniform Quantities only of Liquid can be +poured._ + + +[Illustration: Diagram of apparatus as described in text] + +The following is the construction of the vessel called a dicæometer, +which, having been filled with liquid, discharges an equal quantity +every time it is inverted. Let A B (fig. 41), be a vessel the neck +of which is closed by the partition A B: near its bottom let there +be a small globe, C, holding the measure of water we intend to flow +out. Through the partition insert a small and very fine tube, D E, +communicating with the globe. In the lower part of the globe perforate +a small hole, F, from which a pipe, F G, extends upwards, running +just beneath, and communicating with, the handle of the vessel which +is hollow. Near the hole just mentioned make another at L towards the +body of the vessel: the handle also must have a vent at H. Having first +stopped the vent H we must fill the vessel with liquid through a hole +which must afterwards be carefully closed, or the vessel may even be +filled through the tube D E itself, a fine hole, however, being made in +the body of the vessel through which the air can be driven out; and the +globe C will be filled with liquid at the same time through the tube D +E. Now, if we invert the vessel and set the vent H free, the liquid in +the globe C and the tube D E will flow out. If we again close the vent +and restore the vessel to its original position, the globe and tube +will be filled again, for the air they contain will be driven out by +the liquid rushing in; and, when the vessel is once more inverted, a +like quantity of liquid will again flow out, except indeed with some +difference as to the tube D E, for it will not be always filled, but as +the vessel grows empty it will be empty itself: this difference however +is extremely small. + + + + +42. _A Water Jet actuated by compressed Air from the Lungs._ + + +[Illustration: Diagram of apparatus as described in text] + +There are vessels from which water is forced up by blowing into them. +Through the neck of the vessel (fig. 42), a tube is inserted, reaching +nearly to the bottom, and soldered in at its mouth. Stop this mouth +with the finger, and pour in some liquid through a hole: then, having +blown into the vessel through the same hole, close it by means of a +key, and set free the mouth of the tube; the liquid will be made to +spout up through the orifice by the compressed air which was blown in. + + + + +43. _Notes from a Bird produced at intervals by an intermittent Stream +of Water._ + + +[Illustration: Diagram of apparatus as described in text] + +The notes of birds are produced at intervals as follows. Take an +air-tight vessel (fig. 43), through which a funnel is inserted, the +tube being far enough from the bottom of the vessel to allow of the +passage of water. Above the funnel is placed a hollow vessel, turning +on pivots, and having a weight below, into which water is continually +carried. So long as the vessel on the pivots is empty it will be found +to remain upright, for a weight is attached to its bottom; but, when +the vessel is filled the water is overturned into the air-tight vessel, +and the air contained in the vessel being driven out through a small +pipe will produce the sound. The vessel is emptied of water by means +of a bent siphon, and, while it is being emptied, the vessel on pivots +is again filled and overturned. It will be requisite that the stream +of water should not fall into the centre of the vessel on pivots, that +when filled it may be inverted speedily. + + + + +44. _Notes produced from several Birds in succession, by a Stream of +Water._ + + +[Illustration: Diagram of apparatus as described in text] + +Sounds are produced at intervals in another way as follows. A vessel is +taken (fig. 44), provided with several transverse partitions. In the +chambers are placed siphons conducting into the chambers beneath, the +streams through them being unequal. In the lower compartment is placed +the pipe which produces the sound, and the stream of water falls into +the upper compartment. It will be found that when the upper chamber +is filled, the water passes through the siphon placed there into the +chamber below, until it has arrived at the lowest, and the vessel being +air-tight, the air in this chamber is driven out through the pipe and +produces the sound. + + + + +45. _A Jet of Steam supporting a Sphere._ + + +[Illustration: Diagram of apparatus as described in text] + +Balls are supported aloft in the following manner. Underneath a +cauldron (fig. 45), containing water and closed at the top, a fire is +lighted. From the covering a tube runs upwards, at the extremity of +which, and communicating with it, is a hollow hemisphere. If we put a +light ball into the hemisphere, it will be found that the steam from +the cauldron, rising through the tube, lifts the ball so that it is +suspended. + + + + +46. _The World represented in the Centre of the Universe._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a transparent globe containing air and liquid, and +also of a smaller globe, in the centre, in imitation of the world. Two +hemispheres of glass are made (fig. 46): one of them is covered with a +plate of bronze, in the middle of which is a round hole, To fit this +hole a light ball, of small size, is constructed, and thrown into the +water contained in the other hemisphere: the covered hemisphere is +next applied to this, and, a certain quantity of liquid having been +removed from the water, the intermediate space will contain the ball; +thus by the application of the second hemisphere what was proposed is +accomplished. + + + + +47. _A Fountain which trickles by the Action of the Sun’s Rays._ + + +[Illustration: Diagram of apparatus as described in text] + +The “fountain” as it is called may be made to trickle as long as the +sun falls upon it. Let there be an air-tight pedestal, A B C D (fig. +47), through which a funnel is inserted, its tube extending within a +very little of the bottom. Let E F be a globe, from which a tube leads +into the pedestal, (reaching nearly to the bottom of the pedestal and +to the circumference of the globe,) while a bent siphon, fitted into +the globe, leads into the funnel. Now pour water into the globe; and +when the sun falls upon the globe, the air in it, being heated, will +drive out the liquid, which will be carried along the siphon G, and +pass through the funnel into the pedestal. But when the globe is in the +shade, the air having escaped through the globe, the tube will again +suck up the liquid, and fill the void which had been produced; and this +will take place as often as the sun falls upon the globe. + + + + +48. _A Thyrsus made to whistle by being submerged in Water._ + + +[Illustration: Diagram of apparatus as described in text] + +By immersing a thyrsus in water to produce the sound either of a +pipe or of any bird. Let A B C D (fig. 48), be a thyrsus; and at the +extremity of its head, which must be hollow and shaped like a fir-cone, +let there be an orifice D. Close the shaft a little below the mouth by +the partition A E, and place near it a small pipe, F, just beneath the +mouth of the tube, and passing through an orifice in the partition. +If we insert the thyrsus in water and force it downwards, the air +contained in it being driven out by the water will produce a sound. +If there is nothing but the pipe we shall have a whistle only; but if +there is any quantity of water under the partition there will be a +gurgling sound. + + + + +49. _A Trumpet, in the Hands of an Automaton, sounded by compressed +Air._ + + +[Illustration: Diagram of apparatus as described in text] + +A figure stands upon a pedestal having a trumpet in its mouth: if it +be blown into, the trumpet shall sound. Let A B C D (fig. 49), be an +air-tight pedestal on which a figure stands, and within the pedestal +let there be a hollow hemisphere, E F G, covered over at the top and +having small holes in the bottom. From the hemisphere a tube, H F, +extends upwards into the figure in the direction of the trumpet, which +is provided with a mouthpiece. Pour liquid into the pedestal through a +hole which must be afterwards stopped again by means of [a valve or tap +called] a smerisma. Now, if we blow into the bell of the trumpet, the +air passing from us will force out through the holes the water in the +hemisphere, which will mount up into the pedestal: but when we withdraw +the breath, the water will enter the hemisphere again and force out the +air, which, passing out through the mouthpiece, will produce the sound +of a trumpet. + + + + +50. _The Steam-Engine._ + + +[Illustration: Diagram of apparatus as described in text] + +Place a cauldron over a fire: a ball shall revolve on a pivot. A fire +is lighted under a cauldron, A B, (fig. 50), containing water, and +covered at the mouth by the lid C D: with this the bent tube E F G +communicates, the extremity of the tube being fitted into a hollow +ball, H K. Opposite to the extremity G place a pivot, L M, resting on +the lid C D; and let the ball contain two bent pipes, communicating +with it at the opposite extremities of a diameter, and bent in opposite +directions, the bends being at right angles and across the lines F G, L +M. As the cauldron gets hot it will be found that the steam, entering +the ball through E F G, passes out through the bent tubes towards the +lid, and causes the ball to revolve, as in the case of the dancing +figures. + + + + +51. _A Vessel from which flowing Water may be stopped at pleasure._ + + +[Illustration: Diagram of apparatus as described in text] + +If a bowl stands upon a pedestal and has an open water-spout, the +discharge shall suddenly cease, though there be no slide or tap +attached to shut the spout. Let A B (fig. 51), be the bowl on the +pedestal C: through the bottom of the bowl and the pedestal insert a +tube, D E F, terminating in a spout; and at the handle of the vessel +fix a bar, G H, against which another bar, K L, may move about the pin +H: at the extremity K place a vertical bar, K M, moving about the pin +K: to this bar let a box, N X, be attached at M, having weight, and +large enough to inclose the tube D E F. When the bowl is full, if we +depress the extremity L of the bar, the box N X will ascend, and, when +this is raised, the water in the bowl will be carried out through the +tube D E F: but if the extremity L be set free, the box will descend +and encompass the tube D E F, and the air it contains, having no way of +escape, will disconnect the liquid round the tube D E F, and prevent +it from being further carried out through the mouth D. When we again +depress the extremity L the spout will run as before. + + + + +52. _A Drinking-Horn in which a peculiarly formed Siphon is fixed._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a drinking-horn such that, if a cover of glass be +placed upon it, while a discharge is going on from the vessel, the +liquid shall ascend into the glass cover and be thrown back. A B C +(fig. 52), is a drinking-horn, closed by the covering D E; and from D E +extend two tubes, F G, H K, one of them, H K, leading into the interior +of the vessel, the other, F G, leading outside. A glass cover, M N, +incloses this; and in the top, D E, outside the glass vessel, is an +aperture, X, through which water may be poured. When the horn is filled +through this aperture, the tube H K will be filled at the same time, +and as the water is poured in it will ascend into the glass vessel so +as to be carried outside through the tube F G. Thus we shall have the +arrangement of a bent siphon, of which H K is the smaller leg and F +G the greater, so that it will attract the liquid in the horn as it +ascends into the cover; it will also attract the air contained in the +cover, which is lighter than the liquid, and the water will appear to +be thrown back into the void space left by the air and to descend by +its own weight; for this upward motion is contrary to its nature. + + + + +53. _A Vessel in which Water and Air ascend and descend alternately._ + + +[Illustration: Diagram of apparatus as described in text] + +There is also another contrivance by which liquid is borne steadily +upwards and remains, so as to seem perpetually ascending. Let A B (fig. +53), be a perfectly air-tight pedestal, furnished with a partition, C +D, and a cylindrical glass cover, E F, also perfectly air-tight. In the +cover E F let there be a tube, G H, reaching nearly to the top, and +passing through an orifice in the partition C D, and another tube, K +L, passing through the top of the pedestal but not descending quite so +low as the partition. In the pedestal, and outside the glass cover, let +there be an aperture, M, through which the vessel A D is to be filled, +and near the bottom of the pedestal a spout, N; also one other tube, X +O, passing through the partition and reaching nearly to the bottom of +the pedestal, through which the vessel C B may be filled. If the spout, +N, be closed the air in C B will pass out through the tubes G H, K L, +and the hole M; and when C B is full we must fill A D through the hole +M, for the air contained in it will pass out through the same hole. +Now, if we set the spout N free, the air in the glass cover will pass +through the tube G H into the void space left in C B, and water will +ascend from A D through the tube K L into the void space left in the +cover, while into the void of the vessel A D air will enter through +the aperture M; and this will go on until the glass cover is filled: +but the spaces A D, C B, E F, must be of equal capacity that the air +and water may take the place of one another. When C B is exhausted and +the continuity of the air is broken, the water will again descend out +of the glass cover into A D, air passing into the cover through the +spout N and the tube G H. The air in A D will pass out through the +aperture M. + + + + +54. _Water driven from the Mouth of a Wine-skin in the Hands of a +Satyr, by means of compressed Air._ + + +[Illustration: Diagram of apparatus as described in text] + +If wind is blown through the mouth of certain figures, they spout +up water through some other place. For example, if a satyr holds a +wine-skin, water shall be spouted up through the skin. A B C D (fig. +54), is an air-tight pedestal on which the figure is placed; through +the mouth of the figure a tube, E F, is inserted, communicating with +the pedestal, and having underneath it a small plate, G H, which +closes the aperture F of the tube, and is supported by pins to which +buttons are attached, that the plate may not fall off. Another tube, +K L, is passed through the pedestal, of which the extremity, K, must +be contiguous to the point at which the water-jet is to be, and the +extremity, L, reach to the bottom of the pedestal, leaving only a +passage for the water. At the extremity K there must be a valve or tap +by which the aperture K, which is very small, may be shut. Now if we +pour any quantity of water into the pedestal through a hole, which we +must afterwards stop, and, having closed the aperture K, blow in air +through the tube E F, the air blown in will thrust aside the plate and +descend into the pedestal: and, if this is done several times, the +air in the pedestal will be compressed and close the plate. Let the +valve or tap be opened, and after a short time the compressed air will +drive the liquid in the pedestal violently out through the aperture K, +until all the liquid is spouted up, and the air is brought back to its +natural state, that is, in which it is no longer subject to compression. + + + + +55. _A Vessel, out of which Water flows as it is poured in, but if the +supply is withheld, Water will not flow again, until the Vessel is half +filled; and on the supply being again stopped, it will not then flow +until the Vessel is filled._ + + +[Illustration: Diagram of apparatus as described in text] + +There are some vessels which, when water is poured in, flow +immediately, but, if we discontinue pouring for a short space, do +not flow again, though water is poured in afresh, till they are half +full, when they begin to flow once more; and if we discontinue again, +do not flow any more till they are quite full. Let A B (fig. 55), +be a vessel containing, concealed in its interior, three siphons, C, +D, E, one leg of each being near the bottom of the vessel, +while the other, fashioned into a water-spout, conducts outside the +vessel. At the outer extremities of the siphons, apply vessels, F, +G, H, the bottoms of which are far enough from the orifices of +the siphons to admit the passage of water between; and let all this be +encompassed by another vessel, as it were a pedestal, K L M N, which is +provided with a spout at X. Let the bend of the siphon C be close to +the bottom of the vessel A B; that of D, half way up its height, and +that of E, near the neck. Now, if we pour water into the vessel A B, it +will immediately flow through the siphon C since its bend is near the +bottom: but, if we cease pouring, the liquid poured in will be drawn +off through the pipe F, and the vessel F will be found full of water, +while the other part of the siphon C will be full of air. Consequently, +when liquid is again poured into the vessel, it will not pass through +the siphon C, owing to the air which is contained in the siphon between +the water which is being poured in and that in the vessel F. The liquid +will therefore rise as high as the bend of the siphon D, which is at +the middle of the vessel, and then it will begin to flow: but, if we +again cease pouring, the same will happen as has been explained in the +case of the siphon C. A like result must be imagined with the siphon +E. It will be necessary to pour in the stream gently, that the air +intercepted in the siphon may not be forcibly driven out. + + + + +56. _A Cupping-Glass, to which is attached an Air-exhausted +Compartment._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a cupping-glass which shall attract without the aid +of fire. Let A B C (fig. 56), be a cupping-glass, such as is usually +applied to the body, having a partition across it, D E: through the +bottom of the cupping-glass let two sliding tubes be inserted, F G +being the outer tube and H K the inner; and in these, but outside the +cupping-glass, pierce corresponding holes, L and M. Let the inner +extremities of both the tubes be open, but the outer extremity of +H K be closed and provided with a handle. Under the partition D E +place another pair of sliding tubes, N X, like those just described; +but the corresponding holes must be within the cupping-glass, and be +precisely adapted to a hole in the partition. When these perforations +are complete, let the handles of the sliding tubes be turned round, so +that the holes in the lower tubes may be in a line, while those under +the partition, not being allowed to coincide, remain closed. Now, the +chamber D C being full of air, by applying the orifice L M to the mouth +we can suck out a portion of that air; and then, by turning the handle +again and not removing the tubes from the mouth, we can keep the air +in the vessel C D rarefied; and this must be repeated until we have +drawn off a large quantity of air. Then, applying the glass to the +flesh in the usual manner, we open the holes in the sliding tubes N X +by means of the handle; and it must follow that some of the air in the +vessel A D E will pass into the place of the air withdrawn from C D, +while into the void thus created both the flesh and the matter about +it will be drawn up through the interstices of the flesh which we call +invisible spaces or pores. + + + + +57. _Description of a Syringe._ + + +[Illustration: Diagram of apparatus as described in text] + +The instrument called a pyulcus acts on the same principle. A hollow +tube, of some length, is made, A B (fig. 57); into this another tube, +C D, is nicely fitted, to the extremity C of which is fastened a small +plate or piston, and at D is a handle, E F. Cover the orifice A of the +tube A B with a plate in which an extremely fine tube, G H, is fixed, +its bore communicating with A B through the plate. When we desire to +draw forth any pus we must apply the extreme orifice of the small +tube, H, to the part in which the matter is, and draw the tube C D +outwards by means of the handle. As a vacuum is thus produced in A B +something else must enter to fill it, and as there is no other passage +but through the mouth of the small tube, we shall of necessity draw +up through this any fluid that may be near. Again, when we wish to +inject any liquid, we place it in the tube A B, and, taking hold of E +F, depress the tube C D, and force down the liquid until we think the +injection is effected. + + + + +58. _A Vessel from which a Flow of Wine can be stopped, by pouring into +it a small Measure of Water._ + + +[Illustration: Diagram of apparatus as described in text] + +If there be a vessel full of wine and provided with a running spout, +when a cyathus, or small measure, of water is poured upon the neck of +the vessel, the discharge of wine shall cease, but, if a second measure +of water is poured on, this last shall flow out with the former, or +the two measures of water shall flow out through two different spouts; +and, after all the water is drawn off, the wine shall flow again from +the centre spout: moreover, this shall happen as often as any liquid +is poured on and flows out. Let A B (fig. 58), be a vessel with a +spout, C, at the bottom, and closed at the neck by the partition D E +from which extends a tube, F G, encircled by another tube which is +sufficiently removed from the partition to allow of the passage of +water, as in the case of the inclosed diabetes. Through the partition +insert another tube, H K, projecting to a less height above the +partition than the former tube, and branching off below into two +spouts L and M; and let this tube also be encircled by another tube +distant a small space from the partition: furthermore let the vessel +have a vent N just under the partition. Now, if, after closing the +spouts, we pour in the wine, it will pass into the body of the vessel +through the tube F G, for the air will escape through the vent N: but +when we close the vent and set the spouts free, the liquid intercepted +in the tube H K will flow through L and M, and that contained in the +vessel through C. If, however, while C is still running, we pour a +small measure of water upon the partition, the air will no longer be +able to enter through F G, and the discharge through C will cease: but +if a second measure is poured on, the water will rise above the tube +H K, and be carried through into the spouts L and M, the whole being +drawn up; and then, the tube F G being opened to the air will enable +the spout C to flow as before. This result will take place as often as +we pour on the measures of water. + + + + +59. _A Vessel from which Wine or Water may be made to flow, separately +or mixed._ + + +[Illustration: Diagram of apparatus as described in text] + +From a vessel full of pure wine sometimes the wine flows; if water is +poured in, pure water flows out; then again pure wine; and, if it is +desired, when the water is poured in a mixture shall be discharged. +Let A B (fig. 59), be a vessel, having a partition near the neck, +C D, through which a tube, E F, is inserted, passing out below and +terminating in a spout. In the tube E F, within the vessel and near +the bottom at G, let there be a fine hole, and a vent under the neck +at H. Now, if we close the spout F, and pour in the wine, it will pass +into the body of the vessel, the air escaping through the vent H: but +if we stop the vent and set the spout free, nothing will flow out +except what is intercepted in the tube E F. If water is then poured in, +it will flow out pure, and, when the vent is set free, a mixture is +discharged: if nothing more is poured in, pure wine will flow. + + + + +60. _Libations poured on an Altar, and a Serpent made to hiss, by the +Action of Fire._ + + +[Illustration: Diagram of apparatus as described in text] + +When a fire is kindled on an altar, figures placed near shall offer +libations, and a serpent hiss. Let there be a hollow pedestal, A B +(fig. 60), on which is an altar, C, containing within it a tube, D E, +which descends from the hearth of the altar to the pedestal, and then +branches off into three tubes, E F leading to the mouth of the serpent; +E G H to a wine vessel K L, (the bottom of which must be higher than +the figure M,) and fastened to the lid of K L cross-bar fashion; while +the other tube E N X, in like manner, extends into another wine +vessel O P, also terminating in a cross-head. Both these tubes must +be soldered into the bottoms of the vessels, and in each wine vessel +there must be a bent siphon, R S, and T U, one extremity of each being +immersed in the wine, and the other, (from which extend the hand +of the figure which is to pour the libation,) passing, air-tight, +through the side of the wine vessel. When the fire is about to be +kindled, pour first a little water into the tubes, that they may not +be burst by the dry heat, and close up everything that no air may pass +through. The hot air, becoming mixed with the water, will ascend along +the tubes to the cross-heads, and through them it will exert pressure +on the wine, and carry it to the bent siphons R S and T U. The wine +flowing through the hands of the figures produces a libation as long as +a fire is burning on the altar. The other tube, conveying the hot air +to the mouth of the serpent, will cause the serpent to hiss. + + + + +61. _Water flowing from a Siphon ceases on surrounding the End of its +longer Side with Water._ + + +[Illustration: Diagram of apparatus as described in text] + +Let there be an air-tight vessel provided with an open spout, and by +its side a thyrsus under which is a cup full of water: if the cup is +removed, as long as it is withdrawn, a small stream shall flow from +the mouth; but when the cup is pushed back, the spout shall run no +longer. Let A B (fig. 61), be the vessel described, having its neck +closed by the partition C D; from C D, and fitted air-tight in it, a +tube, E F, extends, about which lies another tube, K L, forming an +inclosed diabetes. With K L another tube, M N, communicates, of which +the mouth M is open, while the outer leg is placed in a cup, O X, into +which water has been poured until it is full; it is clear that so much +of the leg of the siphon as is in the cup will be filled at the same +time. Into the neck of the vessel A B a little water must be poured, +just enough to close all entrance for the air; and, when A B is full, +the spout P, though open, will not run, since the air has no means of +entrance, because of the water poured into the neck. But if the cup +is drawn slightly downwards, some portion of the leg of the siphon +which is in the cup must be emptied, and into the part emptied the +contiguous air will be drawn: this air will attract some of the water +which was poured into the neck, so that the water shall rise above +the mouth F; and hence, the air having found an entrance, the spout P +will run until the cup O X is pushed up again, causing the water to +return to its old position and to close the passage for the air so that +the spout will cease to flow. This will happen as often as the cup is +withdrawn and applied: it is necessary however that the cup be not +wholly drawn away, that the siphon leg may not be wholly emptied. Let +the tube M N be fashioned like a thyrsus, R N being its shaft: thus the +spectacle will be properly arranged. + + + + +62. _A Vessel which emits a Sound when a Liquor is poured from it._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a flagon which utters a sound when liquid is forced +from it. Take a flagon (fig. 62), such as is about to be described, +the neck of which is closed by the plate A B, and the mouth by C D; +and through both these partitions, fitting into them air-tight, let +a tube, E F, be inserted. G H is the handle of the flagon, and K L a +tube placed in the opposite side of the neck, fitting closely into the +partition A B and far enough distant from C D to allow of the passage +of water: in C D let there be a small pipe M such as will utter sound. +The flagon may be filled through the tube E F, the air passing out +through the tube K L and the pipe M; and if we take the handle of the +flagon and incline it so as to pour out the contents, water will flow +out of the vessel through the tube E F, and into the neck B C through K +L: the air contained in the neck being forced out through M gives forth +a sound. There should be another hole in A B through which air may pass +again when the vessel is righted. + + + + +63. _A Water-Clock, made to govern the quantities of Liquid flowing +from a Vessel._ + + +[Illustration: Diagram of apparatus as described in text] + +A vessel containing wine, and provided with an open spout, stands upon +a pedestal: it is required by shifting a weight to cause the spout to +pour forth a given quantity,—sometimes, for instance, a half cotyle (¼ +pint), sometimes a cotyle (½ pint), and, in short, whatever quantity we +please. A B (fig. 63), is the vessel into which wine is to be poured: +near the bottom is a spout, D: the neck is closed by the partition E +F, and through E F is inserted a tube, G H, reaching nearly to the +bottom of the vessel, but so as to allow of the passage of water. K L +M N is the pedestal on which the vessel stands, and O X another tube +reaching within a little of the partition and extending into the +pedestal, in which water is placed so as to cover the orifice O, of +the tube. Fix a rod, P R, one half within, and the other without, the +pedestal, moving like the beam of a lever about the point S; and from +the extremity P of the rod suspend a water-clock, T, having a hole in +the bottom. The spout D having been first closed, the vessel should be +filled through the tube G H before water is poured into the pedestal, +that the air may escape through the tube X O: then pour water into the +pedestal, through a hole, until the orifice O is closed, and set the +spout D free. It is evident that the wine will not flow, as there is +no opening through which air can be introduced: but if we depress the +extremity R of the rod, a portion of the water-clock will be raised +from the water, and, the vent O being uncovered, the spout D will run +until the water suspended in the water-clock has flowed back and closed +the vent O. If, when the water-clock is filled again, we depress the +extremity R still further, the liquid suspended in the water-clock will +take a longer time to flow out, and there will be a longer discharge +from D: and if the water-clock be entirely raised above the water, the +discharge will last considerably longer. To avoid the necessity of +depressing the extremity R of the rod with the hand, take a weight Q, +sliding along the outer portion of the rod, R W, and able, if placed at +R, to lift the whole water-clock; if at a distance from R, some smaller +portion of it. Then, having obtained by trial the quantities which we +wish to flow from D, we must make notches in the rod R W and register +the quantities; so that, when we wish a given quantity to flow out, we +have only to bring the weight to the corresponding notch and leave the +discharge to take place. + + + + +64. _A Drinking-Horn from which a Mixture of Wine and Water, or pure +Water may be made to flow alternately or together, at pleasure._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a drinking-horn from which at first a mixture shall +flow; when we please, on pouring in water, water alone, and then again +a mixture. Let A B (fig. 64), be a drinking-horn, its neck closed by +the plate C D, through which is inserted a tube, E F, leading to the +orifice F, and having a hole, G, bored in it within the vessel: in the +vessel just under the partition make a vent H. Now, if we close the +orifice F and pour in the mixture, it will pass into the body of the +vessel through the hole G; and if we set F free, the mixture will flow +through it, the air entering by the vent H. Again, if we close H and +pour in pure water, the mixture will no longer flow as the air has no +means of entrance, but pure water; and, when H is set free, both will +flow, the water and the mixture, or rather a mixture which is produced +from the two united. + + + + +65. _A Vessel from which Wine or Water may be made to flow separately +or mixed._ + + +[Illustration: Diagram of apparatus as described in text] + +If water is poured into a vessel standing upon a pedestal and provided +with a spout somewhat above its bottom, at one time pure water flows +out, at another a mixture of wine and water, and then unmixed wine +alone. Let A B (fig. 65), be the vessel, standing upon a pedestal and +provided with the spout C D, of which the orifice C is above the bottom +of the vessel. Close the neck of the vessel with the partition E F, +and through E F insert the tube G H, projecting slightly above the +partition and extending to the bottom of the vessel except that a space +is left sufficient for the passage of water. In the body of the vessel, +and projecting without it, let there be another tube K L, under which +a vessel of unmixed wine, K M, is to be placed: in the partition E F +pierce a very fine hole N. If, when these arrangements are complete, +we pour water into the vessel through the neck, the liquid lying round +the projection of the tube will remain in the neck; but all above this +will be carried into the body of the vessel, and when it has reached +the orifice C of the spout, there will be a discharge of pure water. +When a stream has begun to issue from the spout, the unmixed wine in +the vessel K M will be drawn up at the same time, on the principle of +the siphon, and a mixture will be discharged; and when the water is +exhausted, the pure wine will flow by itself, except indeed that the +water about the partition E F will be attracted at the same time. When +the small quantity of water on E F has all run through N, the air will +enter and break the continuity and there will be no further discharge. + + + + +66. _Wine discharged into a Cup in any required quantity._ + + +[Illustration: Diagram of apparatus as described in text] + +Let there be a vessel filled with wine and provided with a spout +under which a drinking cup is placed: wine shall run into the cup in +any required quantity. Let A B (fig. 66), be the vessel containing +wine, and C D the spout, the upper surface of which at the extremity +C is so smooth that, when a valve in the form of a kettle-drum E F is +placed upon it, water is excluded. On the handle of the vessel fix the +vertical rod G H, on which, as on a fulcrum, another rod K L vibrates: +again place another rod, M N, under the pedestal, moving about the +point X, and attach two more rods K O, L P, moving on pivots in such +a way that, if the extremity M of the bar be depressed, the valve E +F is raised, and the spout is opened and sends out a stream, but is +closed again when M is suffered to return. Let the bar M N support the +drinking cup R, into which we wish to receive the given quantity of +liquid: the cup must be placed beneath the spout. Take a weight, S, +capable, by means of a ring, of being shifted along the projection M O +of the rod: and when S has been brought towards M, the spout will be +opened and send its stream into the cup, but as the cup grows heavy +the weight will be raised again and the spout closed. That the wine +may flow out in the required quantity, place in the cup any measure +of liquid, for instance, a cotyle, and, receiving what falls from the +spout in another vessel, shift the weight along the bar to the first +point at which the discharge from the spout ceases: make a mark on the +bar at this point and register one cotyle. We must proceed in the same +manner for a half-cotyle, and two cotylæ, and so on for other measures +as far as we please; and thus we shall have marks for the different +quantities, signifying the points to which the weight must be brought +in order that they may be discharged. Instead of the valve E F, an +air-tight vessel may encircle the spout, so that, as long as the liquid +is kept away by the air within, there will be no discharge through the +spout. + + + + +67. _A Goblet into which as much Wine flows as is taken out._ + + +[Illustration: Diagram of apparatus as described in text] + +Let there be a vessel containing wine and provided with a spout, +underneath which a goblet is placed: whatever quantity of wine is +taken from the goblet, as much shall flow into it from the spout. Let +A B (fig. 67), be the vessel of wine, and C D the spout, to which are +attached the valve E F, and the rods G H, K L, K O, L M as before; and +beneath the spout place the cup P. To the rod K O fix a small basin R +contained in the vessel S T, and let a tube, U Q, connect the vessels S +T and P. When these arrangements are complete, if the vessels S T and +P are empty, the basin R will fall to the bottom of S T, and open the +spout C D. A stream will flow from C D into both the vessels S T and P, +so that the basin will rise and shut the spout again, until we remove +more liquid from the goblet. This result will happen as often as we +remove liquid from P. + + + + +68. _A Shrine over which a Bird may be made to revolve and sing by +Worshippers turning a Wheel._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a shrine provided with a revolving wheel of bronze, +termed a purifier, which worshippers are accustomed to turn round as +they enter. Let it be required that, if the wheel is turned, the note +of the black-cap shall be produced, and the bird, standing on the top +of the shrine, turn round as well; while, if the wheel is turned [in +the opposite direction], the black-cap neither sings nor revolves. +Let A B C D (fig. 68), be the shrine and E F an axis extending across +it, capable of revolving freely, to which the wheel H K, which is to +be turned round, is attached. Let two other wheels be attached to +the axis, in the interior of the shrine, L and M, of which L has a +pulley, and M is a wheel with rays. Round the pulley a cord is wound, +from the extremity of which is suspended a vessel N, shaped like a +conical oven, and provided with a tube X O, terminating in a small pipe +which produces the note of a black-cap: under the conical vessel N +must be placed a vessel of water. From the top of the shrine let fall +a small axis S T capable of revolving freely: at the extremity S let +a black-cap be placed, and at T a wheel with rays, the rays of which +are implicated with, or take into, the rays of the wheel M. It will be +found that, when the wheel H K is made to revolve, the cord is wound +round the pulley and raises the conical vessel N; but, if the wheel is +let go, N descends by its own weight into the water and produces the +sound by the expulsion of the air. The black-cap turns round at the +same time owing to the revolution of the wheels. + + + + +69. _A Siphon fixed in a Vessel from which the Discharge shall cease at +will._ + + +[Illustration: Diagram of apparatus as described in text] + +There are certain siphons which, when placed in vessels, flow until +the vessels are emptied, or the surface of the water has sunk to the +level of the outer orifice of the siphon. Let it be required that the +discharge shall suddenly cease whenever we wish. A B (fig. 69), is +a vessel containing a siphon, C D E, the inner leg of which is bent +upwards as at C F G. Let a vertical rod H K be fixed, on which another, +L M, works as a lever-beam: from L M extends another rod, M N, moving +on a pivot, and provided at the extremity N with a vessel large enough +to encircle the bent portion of the siphon F G. On the rod L M suspend +a weight at L, so that the encircling vessel is raised above the upward +bend of the siphon, and the siphon flows. When we wish the discharge to +cease, we have only to remove the weight at L, and the vessel at N will +descend and encircle the bend G C, so that the siphon will cease to +flow. If it is desired that the stream should continue, we must again +suspend the weight. + + + + +70. _Figures made to dance by Fire on an Altar._ + + +[Illustration: Diagram of apparatus as described in text] + +When a fire is kindled on an altar, figures shall be seen to dance: for +the altars must be transparent, either of glass or horn. Through the +hearth of the altar (fig. 70), a tube is let down turning on a pivot +towards the base of the altar, and, above, on a small pipe which is +attached to the hearth. Communicating with, and attached to, this tube +are smaller tubes lying at right angles to each other, and bent at the +extremities in opposite directions. A wheel or platform on which the +dancing figures stand, is also fastened to the tube. When the sacrifice +is kindled, the air, growing hot, will pass through the pipe into the +tube, and be forced out of this into the smaller tubes; when, meeting +with resistance from the sides of the altar, it will cause the tube and +the dancing figures to revolve. + + + + +71. _A Lamp in which the Oil can be raised by Water contained within +its Stand._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a lamp-stand, such that, if a lamp is placed upon +it, whenever the oil fails, a supply shall be poured into it from the +handle to the amount required, though no vessel is placed upon the lamp +from which the oil can flow into it. Let the lamp-stand be constructed +with a triangular pedestal, like a pyramid, A B C D (fig. 71), hollow +and provided with a partition E F. Let G H, which must also be hollow, +be the shaft of the lamp-stand, and above this shaft place a hollow +cup, K L, capable of containing a considerable quantity of oil. From +the partition E F, and fitting closely into it, a tube, M N, must +extend upwards, leaving a passage for the air between its extremity +and the covering of the cup, K L, on which the lamp is placed. Through +the plate K L insert another small tube X Q, a passage being left for +water between it and the bottom of the cup: the tube X Q must project a +little above the plate K L, and into the projecting part another pipe P +is tightly fitted, closed at its upper extremity, and passing through +the bottom of the lamp so as to be included within it, that there may +be no projection outside. To P solder another pipe, extremely fine, +communicating with it, and reaching to the extremity of the handle, so +that its stream will be carried into the body of the lamp; this pipe +must have an orifice like the others. Under the partition E F let a +tap be soldered leading into the chamber C D E F, so that, when it is +opened, the water in the chamber A B E F will pass into C D E F. In the +plate A B let a fine hole be perforated through which A B E F may be +filled with water; the [air] contained in it will pass out through the +same hole. We now remove the lamp and fill the cup with oil through the +pipe X Q, the air escaping through M N, and again through an open cock +in the bottom C D, when any water in C D E F has first flowed out. The +lamp having been placed on the top by means of the sliding tube P, when +it is required to pour in oil, we must open the tap in the plate E F, +and the water in the chamber A B E F passing into C D E F, the air in +C D E F will reach the cup through the tube M N, and force out the oil +contained in it: the oil will pass into the lamp through the tube X Q +and the pipe attached to it. When we wish the oil to stop running, we +must shut the cock and the discharge will cease. This process can be +repeated whenever it is necessary. + + + + +72. _A Lamp in which the Oil is raised by blowing Air into it._ + + +[Illustration: Diagram of apparatus as described in text] + +The same effect can be produced with the same general construction, +more readily [than] by constructing the pedestal in which the water is. +Let the rest be as before, with the exception of the pedestal and the +water in it; the extremity M of the tube M N, (fig. 72), being fitted +air-tight into an orifice in the surface of the shaft, so as to be +visible outside. Then apply the mouth and blow into the outer orifice; +the breath will pass into the cup and force out the oil through the +tube X O. Thus the same will take place as before; for as often as we +blow into the tube oil will flow into the lamp. It will be necessary +that the extremity of the handle should be bent at right angles to the +orifice of the lamp, that the oil may not be driven outside. + + + + +73. _A Lamp in which the Oil is raised by Water, as required._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a lamp. * * * * * * * * Underneath the lamp place +a vessel perfectly air-tight, A B (fig. 73), either attached to the +lamp or distinct from it. From this let two tubes extend, C D, E F, +communicating with the vessel; the extremity C must reach to the bottom +except a space sufficient for the passage of water, and the tube C D to +the surface of the lamp, having at the extremity D a small cup through +which the water is to be poured in: the tube E F must pass, air-tight, +through the bottom of the lamp. Now if oil be poured through the +opening, it will first pass into the vessel A B, and then, when A B is +full, the tubes C D, E F, and the lamp will be filled also. As the lamp +burns it will become empty, and if we pour in water through the cup, +it will pass into the vessel A B, and the oil will ascend and fill up +the deficiency in the lamp, until it reaches the lamp-nozzle. When the +oil has sunk again, we must do the same, repeating it till the supply +is expended. If it is required to remove the vessel A B, the oil being +retained in the lamp, there must be a valve or tap in the pipes C D, E +F, close to the vessel A B, with keys near the lamp, so that when the +keys are turned, the oil in the lamp, and that in the tubes, shall be +confined. Thus the vessel may be removed from the lamp, and, whenever +it is desired, we may bring them together again, and open the keys. It +is better that the pipe E F should lead to the handle of the lamp, and +C D a little behind it, having the cup which communicates with it, and +through which water will be poured in, placed above; so that the oil +will flow from the handle at the same time that the water is poured +into the cup. + + + + +74. _A Steam-Boiler from which a hot-Air blast, or hot-Air mixed with +Steam is blown into the Fire, and from which hot water flows on the +introduction of cold._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a boiler, on which if a figure is placed, shaped as +if in the act of blowing, the figure shall blow on the coals and thus +the boiler be heated: moreover, if an open spout project near the mouth +of the boiler, nothing shall flow from it until we have first poured +cold water into a cup; and the cold water shall not mix with the hot +until it passes to the bottom of the vessel, while water extremely hot +flows from the spout. The shape of the boiler having been determined +at pleasure, in that part of it intended to hold the water a small +chamber, perfectly air-tight, is intercepted between two perpendicular +partitions. With this chamber a tube, one of those which pass under +the coals, communicates near the bottom, one end of the tube being +closed that no water may enter it from the boiler: the other tubes lead +into the chamber where the water is. Thus when the coals are ignited +they will generate vapour through that tube which leads into the small +chamber. This vapour is carried along a tube which pierces the surface +of the boiler, and through the mouth of the figure on to the coals, +(for the figure must be bent so as to blow downwards;) and as vapour +is always being generated, the figure is always blowing. The vapour is +generated from the fire, and, if we pour a very small quantity of water +into the small chamber, we shall produce more vapour, and the figure, +blowing with great violence, will heat the boiler still higher: just as +in the case of cauldrons exposed to fire we see smoke ascending from +the water. The figure should be moveable by means of a double sliding +tube, to allow of our pouring in the small quantity of water: and, +at the same time, by means of this tube, whenever we do not require +the figure to blow on the coals, we can turn it round in the opposite +direction. On the surface place a small cup from which a tube leads to +the bottom of the boiler, that when cold water is poured in, it may +pass through to the bottom. In order that the boiler may admit of being +filled when water is poured in, and, at the same time, that the water +may not boil over and run out, let another pipe communicate with the +cup on its inner surface, to avoid offending the sight. We will now +expose to view the construction of the boiler. Set up a hollow cylinder +(fig. 74), of which A B is the under surface, and C D the upper; and +construct another hollow cylinder, with the same axis as the former, of +which E F is the under surface, and G H the upper. On the outer edges +of the cylinders let plates be fastened, so as to keep the cylinders +together and cover the edges. In the cylinder E F G H place the tubes, +O K, L X, M N, of which L X perforates the cylinder on one side only at +X, while the other two are bored quite through at each end, and their +orifices either way open into the space between the cylinders. Into the +space intercepted between the two cylinders let down the partitions E +G, H F, intercepting the chamber G H E F, into which the tube described +above, perforated at one side only, penetrates. Place on the surface, +that is on G H, a small tube having the figure attached to, and +communicating with, it; the figure must be perforated throughout, and +incline downwards so as to look towards the coals. That the figure may +cease blowing whenever we like, let the tube on which it sits be fitted +tightly into the other, so that, when we turn it round in the opposite +direction, the figure will no longer blow on the coals but away from +the boiler. We shall also find this sliding tube useful for pouring +water into the chamber G F E H, for, after raising the figure from the +tube on which it is placed, we can pour the water through, and thus +more vapour will be passed along into the figure. On the surface H C +let a cup, R S, be placed; communicating with the interior, and having +a tube at its extremity reaching down to the bottom of the boiler with +the exception of a passage for water. When we desire to let the hot +water out, we must pour in cold through R S; this will pass through +the tube which communicates with the cup into the chamber of the warm +water, which will ascend and flow out through the spout near the neck, +for the cold water which has been introduced will not yet have mingled +with the warm below. As often as this is repeated we shall obtain +warm water for the cold we throw in. In order that we may know when +the boiler will bubble up, the _chasmatium_ is contrived, perforated +throughout, and placed on the neck, a hole having been made in the +surface: it is furnished with a small tube which looks towards the cup +R S, that, when the warm water ascends, it may be carried into the cup. +Such is the construction of the boiler. If we prefer not to cut off the +chamber F G E H through the whole length, but only for a portion of +it, the partitions are made to reach half-way, and another is placed +upon them, admitting through it a tube which extends up to the figure. +When the fire is kindled there will be a rush of vapour from the small +chamber, into which water will be poured as before. + + + + +75. _A Steam-Boiler from which either a hot Blast may be driven into +the Fire, a Blackbird made to sing, or a Triton to blow a Horn._ + + +[Illustration: Diagram of apparatus as described in text] + +Another construction of the same kind is employed to produce the sound +of a trumpet and the note of a blackbird. A boiler is made (fig. 75), +of the same kind as the last, of which all the tubes in the base +are bored through at each end, and near the surface there is a tube +Q E, into which another tube K L is closely fitted, extending into +the chamber for warm air, and moveable about the pin K L. This tube +is perforated by three holes, M, N, X, and similarly three +holes are bored in Q E opposite the holes M, N, X. Near +X, an aperture is made in a support which receives a tube fitting +closely into X and surmounted by the figure, as was described in the +last paragraph: and from M and N two tubes extend, M O, N P, bent at +their upper extremities; these tubes pierce through the surface of the +boiler, into which they are carefully soldered. Through the apertures +other tubes pass, fitting tightly into the tubes P and O. On one of +these tubes is placed the figure of a sparrow, hollow within so as to +receive water: the tube on which the bird sits is bent, and provided +with a tuning-pipe, such as are made to produce notes, and the curved +part of it passes as far as the water contained in the sparrow, so +that, when the sound of the pipe reaches the water, the note of a +blackbird is produced. In like manner the tube N P has another tube +fitting closely into it, on which is placed a figure shaped like a +triton with a trumpet in its mouth: the tube on which the triton is +placed is moreover furnished with the mouthpiece and bell as usual, +and when the vapour reaches these and enters them it will give out the +sound of a trumpet. We must discover by trial when the holes in K L are +opposite the tubes M O and N P, and when to X on which the figure is +placed. Having learnt this, we must make corresponding marks on the pin +K L, that the trumpet may sound, or the figure blow, or the blackbird’s +note be produced, at our pleasure. The arrangements about the cup and +the ascent of the warm water are to be made according to the previous +description. + + + + +76. _An Altar Organ blown by manual Labour._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of a hydraulic organ. Let A B C D (fig. 76), be +a small altar of bronze containing water. In the water invert a +hollow hemisphere, called a _pnigeus_, E F G H, which will allow of +the passage of the water at the bottom. From the top of this and +communicating with it let two tubes ascend above the altar; one of +them, G K L M, bent without the altar and communicating with a box, N +X O P, inverted, and having its inner surface made perfectly level to +fit a piston. Into this box let the piston R S be accurately fitted, +that no air may enter by its side; and to the piston attach a rod, T U, +of great strength. Again, attach to the piston rod another rod, U Q, +moving about a pin at U, and also working like the beam of a lever on +the upright rod W Y, which must be well secured. On the inverted bottom +of the box N X O P let another smaller box, Z, rest, communicating with +N X O P and closed by a lid above: in the lid is a hole through which +the air will enter the box. Place a thin plate under the hole in the +lid to close it, upheld by means of four pins passing through holes in +the plate, and furnished with heads so that the plate cannot fall off: +such a plate is called a valve. Again, let another tube, F I, ascend +from F G, communicating with a transverse tube, A´ B´, on which rest +the pipes A, A, A, communicating with the tube, and having at +the lower extremities small boxes, like those used for money; these +boxes communicate with the pipes, and their orifices B, B, +B, must be open. Across these orifices let perforated lids slide, so +that, when the lids are pushed home, the holes in them coincide with +the holes in the pipes, but, when the lids are drawn outwards, the +connexion is broken and the pipes are closed. Now, if the transverse +beam U Q be depressed at Q, the piston R S will rise and force out the +air in the box N X O P; the air will close the aperture in the small +box Z by means of the valve described above, and pass along the tube +M L K G into the hemisphere: again it will pass out of the hemisphere +along the tube F I into the transverse tube A´ B´, and out of the +transverse tube into the pipes, if the apertures in the pipes and in +the lids coincide, that is, if the lids, either all, or some of them, +have been pushed home. + +In order that, when we wish any of the pipes to sound, the +corresponding holes may be opened, and closed again when we wish the +sound to cease, we may employ the following contrivance. Imagine one +of the boxes at the extremities of the pipes, C D, to be isolated, D +being its orifice, E the communicating pipe, R S the lid fitted to it, +and G the hole in the lid not coinciding with the pipe E. Take three +jointed bars F H, H M, M M^2, of which the bar F H is attached to the +lid S F, while the whole moves about a pin at M^3. Now, if we depress, +with the hand, the extremity M^2 towards D the orifice of the box, we +shall push the lid inwards, and, when it is in, the aperture in it will +coincide with that in the tube. That, when we withdraw the hand, the +lid may be spontaneously drawn out and close the communication, the +following means may be employed. Underneath the boxes let a rod, M^4 +M^5, run, equal and parallel to the tube A´ B´, and fix to this slips +of horn, elastic and curved, of which M^6, lying opposite C D, is one. +A string, fastened to the extremity of the slip of horn, is carried +round the extremity H, so that, when the lid is pushed out, the string +is tightened; if, therefore, we depress the extremity M^2 and drive +the lid inwards, the string will forcibly pull the piece of horn and +straighten it, but, when the hand is withdrawn, the horn will return +again to its original position and draw away the lid from the orifice, +so as to destroy the correspondence between the holes. This contrivance +having been applied to the box of each pipe, when we require any of the +pipes to sound we must depress the corresponding key with the fingers; +and when we require any of the sounds to cease, remove the fingers, +whereupon the lids will be drawn out and the pipes will cease to sound. + +The water is poured into the altar that the superabundant air, (I +mean, of course, that which is thrust out of the box and forces the +water upwards,) may be confined in the hemisphere, so that the pipes +which are free to sound may always have a supply. The piston R S, when +raised, drives the air out of the box into the hemisphere, as has been +explained; and when depressed, opens the valve in the small box Z. By +this means the box is filled with air from without, which the piston, +when forced up again, will again drive into the hemisphere. It would +be better that the rod T U should move about a pivot at T also, by +means of a single [loop,] R, which may be fitted into the bottom of the +piston, and through which the pivot must pass, that the piston may not +be drawn aside, but rise and fall vertically. + + + + +77. _An Altar Organ blown by the agency of a Wind-mill._ + + +[Illustration: Diagram of apparatus as described in text] + +The construction of an organ from which, when the wind blows, the +sound of a flute shall be produced. Let A, A, A, (fig. 77), +be the pipes, B C the transverse tube communicating with them, D E the +vertical tube, and E F another transverse tube leading from D E into +a box G H, the inner surface of which is made level to fit a piston. +Into this box fit the piston K L, which is capable of descending into +it freely. To the piston attach a rod, M N, and to this another, N X, +working on the rod P R. At N let there be a pin moving readily, and +to the extremity X fasten a small plate, X O, near which a rod, S, is +to be placed, moving on iron pivots placed in a frame which admits of +being shifted. To the rod S attach two small wheels, U and Q, of which +U is furnished with pegs placed close to the plate X O, and Q with +broad arms like the sails of a wind-mill. When all of these arms, urged +by the wind, drive round the wheel Q, the rod S will be driven round, +so that the wheel U and the pegs attached to it will strike the plate X +O at intervals and raise the piston; when the peg recedes, the piston, +descending, will force out the air in the box G H into the tubes and +pipes, and produce the sound. We may always move the frame which +contains the rod S towards the prevailing wind, that the revolution may +be more rapid and uniform. + + + + +78. _An Automaton, the head of which continues attached to the body, +after a knife has entered the neck at one side, passed completely +through it, and out at the other; the animal will drink immediately +after the operation._ + + +[Illustration: Diagram of apparatus as described in text] + +An animal shall be made to drink while it is being severed in two. In +the mouth of the animal (fig. 78), let there be a tube, A B, and in the +neck another, C D, passing along through one of the outer feet. Between +these tubes let a male cylinder, E F, pass, to which are attached +toothed bars, G and H. Above G place a portion of a toothed wheel, K, +and, in like manner, beneath H a portion of a toothed wheel, L. Over +all let there be a wheel, M, the inner rim of which is thicker than the +outer; and let sections be cut out of this wheel by the three circles +M, N and X, so that the interval between each division may +be equal to the radius of the wheel. Let the rim or felly be likewise +divided by the circles, so that the circumference of the wheel will +no longer be a circle. Having made an incision, O P, in the upper +part of the neck, and severed the head within the incision, make in +it a circular cavity broader below than above, as it were a female +tube shaped like an axe, which will contain two sides of the hexagon +inscribed in the circle. Let this cavity be R S, in which the entire +rim M N X will revolve in such a manner that, before one division +disappears, the beginning of the next will succeed, and similarly with +the third: so that, if a pin be inserted through the wheel, the wheel +will revolve, and the head of the animal adhere to the neck. Now, if +a knife is passed down through the incision O P, it will enter one of +the clefts of the wheel M, and confine it in the circular cavity; and, +descending lower, it will touch the projecting tooth of the part K of +the wheel, which, being forced downwards, will fit its teeth into those +of the bar G, and the bar being pushed back will bring the cylinder +out of the tube A B. The knife, passing through the intervening space, +will still descend and fall upon the projecting tooth of the part L of +the wheel; and this, being forced downwards, and fitting its teeth into +the toothed bar H, will drive the cylinder out of C D and fit it into A +B. This cylinder is an interior tube fitted into the two tubes, that, +namely, in the mouth of the animal, and that reaching from the incision +in the neck to the hinder foot. When the knife has passed quite through +the neck, and the tube E F has touched both A B and C D, let water be +offered to the animal, and a pair of sliding tubes, placed under the +herdsman, be turned round. When the herdsman revolves, the water above +will flow downwards along the tube C D E F A B, and the current of air +caused by the stream of water will attract the water offered to the +mouth of the animal. Of course the sliding tubes are so arranged that, +as the herdsman turns round, the holes in them coincide. + +The same result can be brought about without the aid of a stream of +water in the following manner. Take once more a pedestal perfectly +air-tight, A B C D (fig. 79), having a partition across the middle, +E F. Let the tube from the mouth of the animal, G H K, lead into the +pedestal, and another tube, L M N, pass through the surface A D and +the partition E F. In the tube, L M N, perforate a hole, X, just above +the partition E F, and let another tube, O P, fit into it closely, +having a hole, R, corresponding with the hole X. To the tube O P +attach a figure of Pan, or some other figure with a fierce look, and, +when the figure is turned towards the animal, it shall not drink, as +though frightened; when the figure turns away, it shall drink. Now, if +we pour water into the compartment A D E F through a hole, G´, which +must afterwards be carefully closed with wax or some other substance, +it will be found that, if the holes R and X are made to coincide, the +water which was poured in will pass into the compartment E B C F. As A +D E F becomes empty, it will attract the air through the mouth of the +figure, which will then drink when a cup is presented to it. + +[Illustration: Fig. 79.] + + + + +[Illustration: Decorative floral border] + + + + +APPENDIX. + + +There are four MSS. of Hero contained in the British Museum. Two belong +to the Harleian Collection: they are numbered 5605 and 5589, and are +assigned, the first to the fifteenth, the second to the sixteenth +century; they are distinguished in the table below by the letters _a_ +and _b_. The others are among the Burney MSS., (108 and 81), and are +both assigned to the sixteenth century: they are cited as _c_ and _d_. +Of these MSS. the first and third, (_a_ and _c_), are by far the most +trustworthy: they generally supply the clauses missing in the printed +text, and often furnish emendations of passages otherwise corrupt. +The other two agree, for the most part, with each other, and with the +printed text, both in the omission of numerous clauses and in the +grossest errors in individual words. It is thus rendered probable that +the defects of the Paris edition are in great measure due, not to the +Editors, but to the MS. followed. + +In the following table of emendations made in the text of Hero as it +appears in the _Veterum Mathematicorum Opera_, those only have been +noticed which appeared curious or important. Many more have been passed +over in which the correction was obvious even without the aid of any +MS. The references are to the page and line of the Paris edition. + + Page and | | + Line of | | + Paris | | + edition. | Reading of Paris Text. | Reading adopted. + ------------+--------------------------+---------------------------- + 147 - 29 | συκίαν _a b d_. | σικύαν _c_. + 150 - 10 | ἐκφανείας | ἐπιφανείας _a b c d_. + — - 34 | τὴν—διαστολὴν | κατὰ τὴν—διαστολὴν _a_. + 151 - 8 | μυκτῆρσιν _d_. | μυκτῆρσιν ἀέρος _a b c_. + — - 51 | ὅσας | ὅσαι _a b c d_. + 153 - 6 | βαθύτερον _d_. | βαρύτερον _a b c_. + — - 23 | στεγνὸν _d_. | στενὸν _a c_. + 155 - 3 | ἀντέχον _a c d_. | ἀντέχων _b_. + 156 - 1 | πνυκτικὸς _a b_. | πνικτικὸς _c_. + | | Commandine reads + | | πνευματικὸς. + — - 24 | ἀλλὰ τὸ μὴ _c_. | ἀλλὰ τῷ μὴ _a b d_. + — - 26 | ἀντεπεξίοντος | ἀντὶ τοῦ ἐπεξίοντος _a b_ + | | _c d_. + 159 - 17 | τὸ ἐν τῷ ὑγρῷ | τὸ ἐν ἀυτῷ ὑγρὸν _a c_. + | (τὸ εν τῷ ὑγρον _b_.) | + 161 - 2 | ἰσθμὸς | ἠθμὸς. This correction, + | | adopted originally on the + | | conjecture of Professor + | | Malden, is supported by the + | | variations of the MSS.; _a_ + | | reads ἱθμος, _b_ ἡθμος. In + | | like manner elsewhere read + | | ἠθμοειδή, &c. for ἰσθμοειδή. + — - 20 | ἐκκεκρυήσεται | οὐκ ἐκρυήσεται + | (so all the MSS.) | + 170 - 30 | ἐκείνοις | ἔκεινον _a b c_. + 172 - 17 | κατέχοντος _c_. | κατέχοντες _a b_. + — - 18 | ἐὰν δὲ ἄνω ὄντος | ἐὰν δὲ ἀνῶμεν ἔτι ἄνω ὄντος + | | _a b c_. + — - 30 | ἴσον, ἐὰν | ὅσον ἐὰν _a b c_. + 173 - 20–24 | This passage is unintelligible as it stands. It should + | be read (with _a b c_) as follows:— + | + | Ἐγχέωμεν οὖν καὶ εἰς τὴν ΜΝΞΟ βάσιν καὶ εἰς τὸν ΠΡ + | κρατῆρα τὸν οἶνον ὥστε πλήρη εἶναι τὸν ΠΡ κρατῆρα, + | καὶ τὴν ΜΝΞΟ βάσιν πεπληρῶσθαι ἄχρι τοῦ Η στομίου + | τοῦ σωλῆνος· τούτου δὲ γενομένου, καὶ φραγέντος + | τοῦ Ε, οὐ διὰ τοῦ ΚΛ σωλῆνος, &c. In the printed + | text all the words from τὸν οἶνον to τὸν κρατῆρα + | inclusive are omitted; so is the οὐ after φραγέντος. + | In the translation the MSS. have been departed from + | in reading “as high as the mouth of the tube G H,” + | instead of “as high as the mouth G of the tube G H.” + | The latter reading is clearly inconsistent with the + | argument. + 174 - 3 | εἰσχωρεῖ καὶ διὰ τοῦ | εἰσχωρεῖν καὶ διὰ τοῦ Υ + | τρήματος | τρήματος _a b c_. + — - 13 | ὁ Κ, ὁ κενὼν | ὁ Κ ἔνων _a b c_. + 177 - 1 | ἀνακεκαμφθέντα ἀγγεῖα | ἀνακεκάμφθω εἰς τὰ ἀγγεῖα + | | _c_. _a b_ have ἀνακεκάμφω. + — - 24 | The printed text is here quite unintelligible. + | We find (beginning of § 24 in translation) these + | words:—ἔστω σμηρισμάτιον ᾧ ἐὰν βουλώμεθα λόγῳ· ἔστω + | δὲ τὸ ὕδωρ τοῦ οἴνου διπλάσιον. The opening sentence + | should be as follows: Ἀγγείου ὄντος κενοῦ καὶ ἑτέρου + | οἶνον ἔχοντος, ὅσον ἐὰν ὕδωρ εἰς τὸ κενὸν ἀγγεῖον + | ἐμβάλωμεν, τοσοῦτον διὰ κρουνοῦ ληψόμεθα κεκραμένον + | ᾧ ἐὰν βουλώμεθα εἶναι λόγῳ· ἔστω δὲ τὸ ὕδωρ τοῦ οἴνου + | διπλάσιον. So _a c_: _b d_ agree with the text. + 180 - 11 | Omit τρίτου with _a c_: _b d_ agree with the text + | in retaining the word, which is unintelligible. + 192 - 3 | ἐπιληφθέντα _b d_. | ἐπειληθέντα _c_. + | | _a_ has ἐπειληφθέντα. + 193 - 26 | ἀποδεδεμένοι | ἀποδεδομένοι _a b c d_. + 195 - 7 | ἀποδεδόσθω | ἀποδεδέσθω _a b c d_. + 197 - 6 | ἄνω _a b c d_. | κάτω, which is given in + | | the margin of _d_, is + | | necessary to the sense. + 200 - 8 | Read ἐναρμοσθεὶς εἰς τὸ σφαίριον φερέτω εἰς τὴν χώνην, + | καὶ ἐμβεβλήσθω εἰς τὸ σφαίριον ὕδωρ. So all the MSS. + | In the text all from φερέτω to σφαίριον inclusive is + | omitted. + — - 14 | After ὑγρὸν add καὶ ἀναπληρώσει τὸν κενωθέντα τόπον. + | So _a b c_. + 202 - 20 | The last clause of § 50 (of the translation) is + | unintelligible as it stands in the printed text. + | For στρέφειν εἰς τὴν χώραν _a_ and _c_ give εἰς τὴν + | σφαῖραν. In the translation σφαῖραν is preferred to + | χώραν, and εἰς omitted. + 205 - 10 } | Clauses of considerable length are missing in the + 206 - 10 } | text from the usual cause. They are supplied in + 185 - 11 } | the translation. + 212 | The arrangement of the three plans for self-acting + | lamps has been altered in conformity with _a_ and _c_; + | _b_ and _d_, agreeing with the printed text. + 216 - 26 | ἐκπίπτοντος | εἰσπίπτοντος _a_. + 223 - 7 | ΓΔ (CD) | ΕΖ (EF): this change has + | | been made on conjecture. + — - 16 | Before ὥστε ἢ has been inserted, without support + | from the MSS. The passage is otherwise + | self-contradictory. + 226 - 23 | διηνοιγμένον _a b c d_. | διενηνεγμένον? + 227 - 21 | This passage is corrupt, but the MSS. give no light. + 228 - 8 | ἐκτὸς | ἐντὸς _a b c d_. + — - 41 | ἐν τοῖς αὐλοῖς _a b c d_.| τοῖς ἐν τοῖς αὐλοῖς? + 229 - 30–40 | The reading of the text is evidently corrupt here, + | but the MSS. do not supply means for correcting it: μίας + | οὔσης may be a corruption of μενούσης; Hero speaks + | elsewhere of a περόνη μένουσα. + 232 - 14 | The text and all the MSS. read ὑπὸ; nevertheless ὑπὲρ + | has been substituted in the translation. If the holes X + | and R were _beneath_ the partition, the action of the + | tubes would fail. + + + + +[Illustration: Decorative floral border] + + + + +INDEX. + + + Air (atmospheric), 1. + + Adamant, 2. + + Anvil, 2. + + Archimedes, 9. + + Air-pump (condensing), 23. + + Altar, 26, 83. + + Apple, 62. + + Arrow, 62. + + Air-engine, 95. + + + Bottle, 3. + + Bitumen, 5. + + Bronze, 7. + + Beam, balance, 11. + + Bar, 19. + + Bird, 29. + + Beam on an axis, 33. + + Ball tap, 36. + + Ball float, 43. + + Beam, 44. + + Bow, 62. + + Boiler, 72, 101, 102, 103. + + Buttons, 76. + + Bellows, (substitute for), 105. + + Bell-crank lever, 106. + + + Cupping-glasses, 4. + + Coal-cinders, 5, 101, 102. + + Cook’s ladle, 21. + + Carpenters’ rule, 25. + + Chain, 32. + + Cork, 36. + + Coin, 37. + + Cock or tap, 41. + + Cylinders, (bored bronze), 44. + + Church organ, 105. + + + Dew, 5. + + Divers, 8. + + Door of temple, 33. + + Dragon, 62. + + + Earth, 1. + + Extinguisher, 33. + + Engine, (steam-), 72. + + + Fire, 1. + + Force, 3. + + Funnel, 29. + + Fir-cone, 70. + + Flagon, 86. + + Finger-organ, keys, 105. + + + Glass, 3, 68, 74, 75, 76, 79, 95. + + Globe, 7, 20. + + Groove, 17. + + + Hammer, 2. + + Heat, 2. + + Horn-shavings, 3. + + Handle, 17. + + Hinges, 25. + + Holy water, 49. + + Hercules, 62. + + Hot-air blast, 100, 101. + + + Iron, 10. + + + Jar, 22. + + + Kettle-drum, 32. + + Key, 41. + + + Light, 9. + + Libation, 26. + + Lathe for turning, 32. + + Lead, 36. + + Lamp-wick, 52. + + Lever-beam, 94. + + + Metal plate, 7. + + Marine torpedo, 10. + + + Nut, (substitute for), 17. + + + Oil, 6. + + Owl, 30. + + Oven, 94. + + Organ-pipes, 105. + + + Pores, 9. + + Priest, 26, 83. + + Priestess, 26. + + Pulley and rope, 32. + + Piston, turned, (metallic), 44. + + Piston-rods, 44. + + Pan, 47. + + Pinion, (toothed), 52. + + Poised cup, 66. + + + Quicksilver, 58. + + + Rod, 32. + + Rack, (toothed), 52. + + Racks, 109. + + + Sand, 2. + + Sponge, 3. + + Smoke, 5. + + Steam, 5, 68, 69, 72, 100. + + Sulphur, 5. + + Sun, 5. + + Sun’s rays, 9. + + Suction, 11. + + Solder, 17. + + Sliding-frame, 17. + + Screw, 17. + + Sieve, 19. + + Spout, 73. + + Syringe, 80. + + Serpent, 83. + + Steel-yards, 87. + + Shrine, 93. + + Spur wheels, 93. + + Sparrow, 104. + + Springs, 106. + + Sectors, (toothed), 109. + + + Tube, 7. + + Tin, 8. + + Trumpet, (mouthpiece and bell), 32. + + Three-way cock, 51. + + Trigger, 62. + + Thyrsus, 70. + + Turn-table, 95. + + Triton, 103. + + Tuning-pipe, 104. + + Tappet-wheel, 108. + + + Universal joint, 45. + + + Vacuum, 1. + + Vent, 21. + + Valve, (circular slide), 23. + + Valve, (clack), 24. + + Valve, (suspended), 37. + + Valve, (spindle), 44. + + Valve, (plane slide), 105. + + + Water-clocks, 1, 87. + + Water, 1. + + Wind, 2. + + Wine, 19. + + Weight, 32. + + Wheels, 49. + + Wine-skin, 55. + + Washing-basin, 55. + + Water-jet, 65. + + Whistle, 70. + + Wheel and axle, 93. + + Wind-mill, 108. + +[Illustration: Shield with initials W.C. being held by a lion] + + + + +[Illustration: Sketch of a boat with sails] + + + + +SKETCH OF THE ORIGIN AND PROGRESS OF STEAM NAVIGATION. + +FROM AUTHENTIC DOCUMENTS. + +BY BENNET WOODCROFT. + +PROFESSOR OF MACHINERY IN UNIVERSITY COLLEGE LONDON. + +_With Seventeen Lithographic Plates and Woodcuts._ Fcap. 4to. 12_s._ +cloth. + + +Although much has been written and published on the subject of Steam +Navigation, the merits of the several inventions by which it has been +brought into practical operation have not in all cases been faithfully +recorded, or duly assigned to their respective authors. + +This defect is intended to be supplied in the following sketch; +first, by a chronological enumeration of the several projectors, +whether subjects of Great Britain or Foreigners; and secondly, by +presenting to the reader a clear and impartial statement of what has +been accomplished by each, viewed either as an original inventor, or +as having been instrumental in promoting the means by which Steam +Navigation has reached its present state of excellence. + +The pretensions of the several inventors are accordingly arranged in +the order of time, and at such length as the limits of the work will +admit. + +Those who have explained the nature and principles of their inventions +are afforded the advantages derivable from such explanations by +quotations from their own writings; while other inventors or patentees, +who have not availed themselves of this mode of giving publicity to a +description of the means by which they have endeavoured to supersede +prior inventions, or to extend their utility, have the benefit of such +remarks as have been elicited by the writings of their own countrymen. + +The sketch accordingly commences by detailing facts which demonstrate +that the use of the Paddle-wheel as an instrument for propelling +boats or vessels is of great antiquity, preceding by ages the first +suggestion of the application of steam as a motive power for that +purpose. + +This is succeeded by a recapitulation of the early projects for +propelling vessels by the aid of the steam-engine, and of the various +modifications proposed or practically adopted at subsequent periods; +thus placing before the reader the means of forming a just estimate of +the pretensions of the several projectors to be ranked as _the real +authors of the present system of Steam Navigation_. + +In conclusion, some of the instruments denominated Screw Propellers +are duly noticed, with authentic statements of the results of various +experiments in which they were applied, and remarks on those generally +in use in Europe and in the United States of America. It will be +obvious that the facts thus detailed were widely scattered, and in +some few instances difficult of access: they have consequently been +collected and arranged from many sources, and the compilation is now +submitted as forming a book of reference which may be found not only +useful, but interesting to those who seek for information as to the +origin and progress of Steam Navigation.—_Preface._ + + + LONDON: TAYLOR, WALTON, AND MABERLY, IVY LANE, + PATERNOSTER ROW. 1848. + + + + +TRANSCRIBER’S NOTE + + +Illustrations in this eBook have been positioned between paragraphs. + +The index was not checked for proper alphabetization or correct page +references. + +Obvious typographical errors and punctuation errors have been corrected +after careful comparison with other occurrences within the text and +consultation of external sources. + +Some hyphens in words have been silently removed, some added, when a +predominant preference was found in the original book. + +Except for those changes noted below, all misspellings in the text, and +inconsistent or archaic usage, have been retained. + + + Pg xix: ‘which’ replaced by ‘the’ to match the title of the section. + 117: ‘Spunge’ replaced by ‘Sponge’. + + +*** END OF THE PROJECT GUTENBERG EBOOK 77400 *** |