Chapter II: Part 2

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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._

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.

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._

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._

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._

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._

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._

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._

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._

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._

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._

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.

27. _The Fire-Engine._

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._

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._