Chapter III: Part 3

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._