Chapter IV: Part 4

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an open spout, and by its side a thyrsus under which is a cup full of water: if the cup is removed, as long as it is withdrawn, a small stream shall flow from the mouth; but when the cup is pushed back, the spout shall run no longer.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 This will happen as often as the cup is withdrawn and applied: it is necessary however that the cup be not wholly drawn away, that the siphon leg may not be wholly emptied.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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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.

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.

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.