Chap. 4.]

Raising Water with Open Tubes.

501

sooner become expanded and broken. When, however, one of these instruments is intended to deliver water at a level with its upper orifice only, then the discharging orifice should resemble that of No. 226, or C D in No. 201, as an increased discharge of the liquid would in that case take place: a greater flow of air would enter on the ascent of the tube, and a larger volume of water flow out on its return.

EXPER. VII.-A number of conical tubes, ten inches long, were prepared. The diameter of the small ends of all was inch, while the large ends were respectively 4 inches, 34, 3, 23, 24, 2, 2, 13, 14, 14 and 1; and besides these, two cylindrical ones of inch and inch bore. With the cylindrical tubes no jet could be produced by any movement given to them, either quick or slow, however deep they were immersed; nor yet when they were inclined. When the conical ones were immersed half their length, and worked without plunging them deeper, no water could be ejected: the cause of this however was not the same in all. In six or seven of the largest, the parts below the surface were too capacious to be filled instantaneously with air through the small orifice above as they were raised. The sound made by the entering fluid (like a person gasping for breath) showed this, especially in the largest. But in the smaller sizes, the air entered as fast as they were raised, and consequently disturbed but slightly the surface of the liquid within.

When any one of them was immersed within an inch of the small end and then moved two or three inches up and down, a jet was thrown out, and from the large ones with considerable force, on account of the greater mass of the liquid put in motion in their lower part. Still, however, the jet did not rise so high from the large as from some of the smaller tubes, because the sides of the former converged so rapidly to the discharging orifice that the liquid particles crossed and counteracted each other as they issued. Short cylindrical ajutages soldered on two of the largest made no sensible improvement. The disadvantages of making the lower parts

too wide or spacious for the entering air fully to occupy, was also very apparent when the tubes were raised five or six inches in working them. The water within not being wholly displaced, it hung in F them as in an inverted tumbler or bucket, and consequently its weight was added to that of the tube. This not only required an increase of force, but the intended effect was diminished and in a great measure destroyed. The same thing of course occurs if a smaller tube be used, with a large additional part to its lower extremity, as at No. 229. To obviate this by furnishing a larger supply than would enter the smaller orifice, we adapted an air tube whose exterior end was covered by a valve opening upwards, as shown in the cut. The

No. 233.

502

Raising Water with Open Tubes.

[Book V. force required to work the larger tubes was very sensible, but with the smaller ones it was scarcely appreciable. Those whose larger ends were 2 inches and 13 inches produced the highest jets, but they were obviously too much tapered for practical purposes, and even the sides of the smallest one named, formed too large an angle to be applied with advantage at great depths.

The tube No. 230, two feet one inch in length, was made of tin plate. It consisted of a conical piece 22 inches long, 14 inches wide at one end, and inch at the other. To the wide end a flaring piece, 3 inches long and 4 diameter at the lower edge, was added. This piece was made of sheet lead for the convenience of forming it. When wholly immersed in water, except 2 or 3 inches by which it was held, this tube threw a jet 15 feet high. By the upward stroke the jet rose 12 feet. When the diverging ajutage A (whose contracted part was the same as the orifice of the tube) was slipped on the latter, the jet was dispersed before it rose 8 feet. An inch was cut off the lower end, leaving the diameter 3 inches, upon which the jet rose to about 14 feet. Another inch was then removed, when it rose still lower; yet it might still, by a quick back stroke, be thrown nearly as high as at the first. It would therefore seem, that although a large flaring end requires more force to raise it than a small one, yet the increased velocity required to be given to the downward stroke, in order to raise the jet to an equal height, comes to much the same thing. There is a way however by which the resistance which a large flaring end meets with from the water may be avoided in the upward stroke, viz. by enclosing the tube in an air-tight cylindrical one, of the diameter of the flaring end, as represented by the dotted lines in No. 230: or the instrument might be inserted in a wooden tube, whose specific gravity was about the same or rather less than that of water.

No. 231 was 3 feet long, formed of copper, and of a regular taper to within four inches of its lower end. Its diameter at the small end was half an inch, and at the lower end 3 inches, to which a piece flared out to six inches was added. By an upward stroke of 18 inches, the jet rose 17 feet; and by a downward stroke of one foot, it rose to the same height. (These measurements, and the others mentioned, relate to the extreme height to which a small part only of the liquid rose. The main body of the jet seldom reached over two-thirds of the distance.) When the upward stroke was continued 23 feet, the rushing air pushed all the water out of the tube, and rose up on the outside.

EXPER. VIII. We next prepared a larger tube, and arranged it so as to be worked in a light wooden frame, which was secured in a wine pipe filled with water. (See No. 233. The wine cask is omitted.) This instrument was deemed equal to any that was tried-the quantity of water, and the elevation to which it was raised, being compared with the force employed. It should not, however, be considered as exhibiting anything like the maximum effect which spouting tubes are capable of producing, because the friction of the liquid in passing through so small an orifice as that of No. 233 was very considerable. The reader is therefore requested to bear in mind, that the larger the bore of these tubes, the more favorable would be the result; and that, although jets of water may be thrown very high by them, yet they are better adapted to raise large volumes of water to small heights.

The tube No. 233 was five feet long. It was composed of one piece 4 feet 4 inches in length, .75 of an inch diameter at one end, and 2.9 inches at the other. To this end a piece 5 inches long was added, which made the diameter 5.5 inches; and to this another piece 3 inches long, which

Chap. 4.]

Raising Water with Open Tubes.

503

The

made the extreme end of the tube 7.5 inches diameter. The tube as thus formed was secured to a straight strip of wood of nearly the same length, by means of three copper straps, which were soldered to the tube and screwed to the wood. (See the figure.) About a foot from each end, and across the back of the strip, two pieces of wood, 3 inches long and 12 wide, were secured. They projected half an inch over each side of the strip, and were beveled at the ends, so as to fit into and slide readily up and down in a dovetailed groove formed on the face of the post F F. This post was secured in an inclined position, as represented. When large tubes are used they should always be inclined, that the water once raised above the orifice may not fall into it again and run back. surface of the water in the cask was 13 inches below the upper end of the tube, and upon working the latter the jet (of an inch diameter) rose 22 feet. A piece of pipe was next slipped on the end, which made the tube a foot longer, and reduced the orifice to half an inch, when the jet rose little if any higher than before. Another tapered piece of pipe was added to the last, making the orifice five-sixteenths of an inch, upon which the jet did not ascend over six or eight feet. An air-pipe, figured at No. 232, was now added, that the water might be fully depressed in the tube on its ascent, but the jet was so pinched at the orifice that no obvious change was perceived.

The upward stroke ought to be so regulated, that the air in rushing down should push nearly all the water out of the tube, that the wave in rising may be urged up with the full pressure of that above it in the reservoir: hence the elevation of the jet produced by the upward stroke of a spouting tube depends chiefly upon the depth of its immersion. But if the upward movement exclude nearly all the water, the downward one if made with due velocity prevents it, or much of it, from entering before the tube itself gets nearly to the end of its stroke, and consequently the effective height of the hydrostatic column is then increased to an extent equal to the length of the stroke. On the other hand, if the upward movement be made so quick that the air has not time to fill the enlarged space below before the stroke is finished, then little or no rise will take place. The operation in this case is the converse of the experiment with the matrass, No. 225.

When the movements of one of these instruments are properly timed, the inertia of the descending air and ascending liquid is peculiarly bene ficial. In ordinary machines, where the direction of moving masses is reversed, or when they are alternately brought into a state of rest and motion, the inertia is overcome by an outlay of the force employed; but this is not the case with spouting tubes. Thus when a tube is raised, the air descends into the vacuity left by the retiring liquid, and when its momentum is expended, its motion is continued by inertia alone, and consequently the water is pushed down still further. Then again, on the ascent of the liquid the elevation of the jet, or the volume discharged, will be increased if the inertia of the rising wave be suffered to expend itself without interference by an untimely movement of the instrument.

A reciprocating rectilinear movement might be given to spouting tubes by a spring-pole, as in the canne hydraulique. The movement, however, should be regulated by that of the wave. This might be accomplished in large tubes by connecting to the moving apparatus a heavy pendulum, whose length could be increased or diminished according to that of the stroke.

If a tank or reservoir be not sufficiently deep for the employment of these tubes, an opening of the proper size and depth might be made at

504

The Soufleur.

[Book V. the corner or side in which to work them. When water is to be discharged on a level with the orifice, the upper part of the tube should slide through another fixed to and standing above the bottom of the receiving cistern, that the liquid when once raised may not run back; and, for the same reason, the tube should be inclined. Among other uses to which they are applicable is that of occasionally watering or washing trees and plants. In public gardens and other places, where a jet d'eau cannot otherwise be conveniently obtained, these instruments might be placed in a reservoir and moved by concealed mechanism, so as to produce one; and although it would consist of a succession of jets, the movements might be so regulated that they would appear but one. The motion of the tube itself might also be hid, by making it play in the interior of a fixed one, above whose orifice it need not protrude. In this manner the air in factories, hospitals, and rooms of private dwellings, might be kept cool, and, by perfuming the water, rendered very agreeable and refreshing in sultry weather. In fact, at every place where a fountain is desirable, a vase and spouting tube might be used.

The experiments we have given are very imperfect, but they may serve to excite those persons who have leisure and opportunity to pursue the subject. This mode of raising water is deserving of a rigid investigation, and will amply repay all the labor expended upon it.

There is a natural illustration of spouting tubes in the Souffleur, or Blower, on the south side of the Mauritius. The action of the waves has undermined some rocks that run out into the sea from the main land, and has worn two passages that open vertically upwards. They are represented " as smooth and cylindrical [conical?] as if cut by a chisel." When a heavy sea rolls in, it fills in an instant the caverns underneath, and finding no other egress, a part is forced up the tubes to an elevation of sixty feet. The moment the waves recede, the vacuum left by them causes the wind to rush into the apertures with a noise that is heard at a considerable distance. See a description of this phenomenon in the Saturday Magazine, vol. vi. p. 77.

Chap. 5.]

Nature's devices for raising Water.

505

CHAPTER V.

Nature's devices for raising water-Their influence-More common than other natural operationsThe globe a self-moving hydraulic engine-Streams flowing on its surface--Others ejected from its bowels--Subterranean cisterns, tubes and siphons-Intermitting springs-Natural rams and pressure engines Eruption of water on the coast of Italy-Water raised in vapor-Clouds-Water raised by steam-Geysers-Earthquakes-Vegetation-Advantages of studying it-Erroneous views of future happiness-Circulation of sap-This fluid wonderfully varied in its effects and movements-Pitcher plant and Peruvian canes-Trees of Australia-Endosmosis-Waterspouts-Ascent of liquids by capillary attraction-Tenacity and other properties of liquids-Ascent of liquids up inclined planes-Liquid drops -Their uniform diffusion when not counteracted by gravity-Their form and size-Soft and hard soldering-Ascent of water in capillary tubes limited only by its volume-Cohesion of liquids-Ascent of water through sand and rags-Rise of oil in lamp wicks and through the pores of boxwood

BEFORE taking leave of artificial machines for raising water, a few of the most prominent of those which nature employs may be noticed; for, after all, the best of human contrivances are but imitations of hers.

The extent to which raising of water is carried by nature is wonderful. Persons who have not reflected on the subject would hardly suspect the influence which this operation exerts on our globe; yet it is one which the Creator has adopted to bring about results upon which the happiness of all things living depend. To the elevation of water into the atmosphere, and its return to the earth, the formation of continents and islands, lakes, rivers, fountains, valleys, plains, gravel, sand, mould, &c. are due. The fertility of soil, growth of vegetables, and life of animals, are also to be attributed in a greater or less degree to the same source.

Of nature's machinery, devices to raise, diffuse and collect water are the most common. They pervade all her works-the most magnificent and the most minute: and if we turn our thoughts to the world at large and contemplate it as a whole, we find it performing the part of an immense hydraulic engine, one which never stops working, and whose energy never flags. In almost every point of view this feature is obvious. In its exterior our planet is rather aqueous than terrene. Three-fourths of its surface are sunk into basins and scooped into channels for the reception and transmission of water; more than one-half is occupied by the ocean, the principal reservoir; while the other half is intersected in every direction by lakes, rivers, and rivulets innumerable, that convey the dispersed liquid back to the sea. The motion imparted to water also exhibits every degree of activity and agitation, from overwhelming torrents and mountainous waves, to the gentle shower that descends as if dropt through the finest cullender, and the placid stream that glides imperceptibly by. Sometimes we behold it running with the speed of a race horse, roaring among rapids, leaping over precipices and darting down cataractshere dashed into spray, there churned into foam; now winding in eddies and gyrating in whirlpools; passing through channels whose paths are tortuous as those of a serpent, and shooting through others straight as an

arrow.

Open channels and reservoirs constitute, however, but a part of nature's hydraulic machinery. In the interior of the earth, are close and air-tight reservoirs, and tubes of every imaginable size and figure, and of incon