Chap. 4.]

Spouting Tabes,

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CHAPTER IV.

Spouting tubes—Water easily disturbed—Force economically transmitted by the oscillation of liquids—Experiments on the ascent of water in differently shaped tubes—Application of one form to siphous—Movement given to spouting tubes—These produce a jet both by their ascent and descent—Experimentswith plain conical tubes—Spouting tubes with air pipes attached—Experiments with various sized tubes—Observations respecting their movements—Advaptages arising from inertia—Modes of communicatingmotion to spouting tubes—Purposes for which they are applicable—The Souffleur.

There is a simple mode of raising water which to oür knowledge hasnever been adopted, nor yet suggested—viz. by straight and open pipes, or,as they might be named, spouting tubes.

Water is raised in the ram (No. 168) by the force which the liquid ac-quires in flowing through descending channels, but in the instruments towhich we now refer, the same effect is produced by its momentum inpassing up vertical ones. So far as respects the force of a liquid in mo-tion, it makes little difference in what direction it moves—whether theliquid rise perpendicularly, or having first descended at one angle it ascendat another. Ä jet d’eau, deducting all resistances, rises with the velocitywith which it would fall through the same space ; but in practice, the ve-locity is diminished by the length, figure and dimensions of the channelthrough which the liquid flows, and of the ajutage from which it escapes.

Every person’s experience teaches him, thät a very small force is suffi-cient to disturb a large body of water, and that the consequent movementof the liquid is long continued after the force is withdrawn. A stone droptinto a tank, or thrown into a pond, causes waves to rise and roll to andfro over their whole surfaces, and some time elapses ere the movementscease. Days and even weeks elapse after a storm is over before the oceanrecovers its previous repose. This effect is the result of the great mobilityof water; its particles move with such extreme facility among themselves,and so actively impart their motion to each other, that a force once com-municated to them is long ere it becomes exhausted. It is the same to acertain extent when waves rise and fall within tubes; for although thefriction of liquids against the sides of these channels is considerable, espe-eially in small ones, still the force in the central parts is but slowly con-sumed. A device therefore by which the oscillation of liquids is employedin transmitting forces, will probably consume as little in tbe transit as anymechanical device known.

It has already been remarked, that the momentum of a flowing liquidsuffers less in passing through a short than through a long tube—througha straight than a crooked one ; and we may add that this is more especiallytrue when the figure of the tube is expreSsly designed to facilitate thepassage of the moving liquid, instead of being uniform in its bore through-out. Now in these particulars spouting tubes are eminently superior toothers, or they may be made so. They are sbort, straight, and of a formadapted to the rising wave within them.

Motion is imparted to water in a spouting tube either by depressing theliquid below the orifice and then admitting it to enter, or by excluding itfrom the tube tili the lower orifice of the latter be sufficiently immersed.If a pipe whose lower end is closed be plunged perpendicularly in water,

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