Part 7

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.