Chap. 5.]

Nature’s devices for raising Water.

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CHAPTER V.

Nature’s devices for raising water—Their influence—More common than other natural operations—The globe a self-moving hydraulic engine—Streams flowing on its surface—Others ejected from itsbowels—Subterranean cisterns, tubes and siphons—Intermitting springs—Natural rams and pressureengines—Eruption of water on the coast of Italy—Water raised in vapor—Clouds—Water raised bysteam—Geysers—Earthquakes—Vegetation—Advantages of studying it—Erroneous views of future hap-piness—Circulation of sap—This fluid wonderfully varied in its effects aud movements—Pitcher plantand Peruvian canes—Trees of Australia —Endosmosis—Waterspouts—Ascent of liquids by capillaryattraction—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 hardsoldering—Ascent of water in capillary tubes limited only by its volume—Cohesion of liquids—Ascentof water through sand and rags—Rise of oil in lamp wicks and through the pores of boxwood

Befork taking leave of artificial machines for raising water, a few of themost prominent of those which nature employs may be noticed ; for, afterall, 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 theinfluence which this Operation exerts on our globe ; yet it is one whichthe Creator has adopted to bring about results up.on which the happinessof 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. Thefertility of soil, growth of vegetables, and life of animals, are also to beattributed in a greater or less degree to the same source.

Of nature’s machinery, devices to raise, diffuse and collect water arethe most common. They pervade all her works—the most magnificentand the most minute : and if we turn our thoughts to the world at largeaud contemplate it as a whole, we find it performing the pari of an immensehydraulic engine, one which never stops working, and whose energy neverflags. In almost every point of view this feature is obvious. In its ex-terior our planet is rather aqueous than terrene. Three-fourths of itssurface are sunk into basins and scooped into channels for the receptionand transmission of water ; more than one-half is occupied by the ocean,the principal reservoir ; while the other half is intersected in every direc-tion by lakes, rivers, and rivulets innumerable, that convey the dispersedliquid back tö the sea. The motion imparted to water also exhibits everydegree of activity and agitation, from overwhelming torrents and moun-tainous waves, to the gentle shower that descends as if dropt through thefinest cullender, and the placid stream that glides imperceptibly by.Sometimes we behold it running with the speed of a race horse, roar-ing among rapids, leaping over precipices and darting down cataracts—here dashed into spray, there churned into foam; now winding in eddiesand gyrating in whirlpools ; passing through channels whose paths aretortuous as those of a serpent, and shooting through others straight as anarrow.

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

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