This depends upon the principle that water transmits force equally in all directions; therefore, strange as it may appear, we meet the paradox that a little water will accomplish as much as a great quantity. Thus, if a slender upright tube be connected with the bottom of a large tank the water will stand at the same height in both, and consequently the trifling amount of water in the tube supports and balances the vast amount in the tank. Suppose the area of the tube were as one to ten thousand. Now, if we should apply the force of one pound on the surface of the water in the tube, an uplifting force of one pound would be communicated to every equal area of a piston resting upon the surface of the water in the tank; so it is evident that with the pressure of one pound we might raise ten thousand pounds.
There are few more interesting proofs that “Peace hath her victories, no less renowned than war,” than that found in the completion of the Erie Canal, whereby a path was made for the vast agricultural products of the west to the metropolis, and thence to all countries.
Re-read the story of that magnificent commemoration of human genius and effort, when, in New York harbor, Governor DeWitt Clinton joined in perpetual wedlock the lake and the sea.
An interesting illustration of the upward pressure of water in seeking its level may often be seen in the dry docks of our great seaport cities, where old ocean is frequently compelled to do heavy work for man by lifting his ships out of water. A vessel is on the shoals; after the storm has subsided a great number of empty air-tight casks are sunk around the ship and fastened to it. The gradual pushing of the water lifting against the casks slowly raises the vessel until she floats.
SHOWING AN ORDINARY PUMP.
WATER AS A LAPIDARY.
Allusion has already been made to the erosive action of water. Every day observation will furnish us examples of this. The pebbles beneath our feet have been rounded and polished by this lapidary. The most beautiful specimens of its handiwork, however, are to be found in crystallization. Snow exhibits many lovely forms. If the flakes are caught on any dark surface we shall readily see that they are fashioned with great symmetry, starlike in form, on the plan of six diverging rays. There is an endless variety formed by additions made to these primaries. Not less beautiful are many of the forms of ice. The Mer-de-Glace of the Alps is pronounced by Prof. Tyndall one of nature’s most resplendent pieces of handiwork. If we may judge from all descriptions, the lofty spires and glittering sides of an iceberg furnish a spectacle sublime and terrible. The vast ice fields of the North, in spite of all their desolation, possess a mysterious charm.
The most favorable condition for the crystallization of any substance is its solution in water. It will thus appear that water is one great source of that marvelous beauty of form which we find in the mineral world. This process of nature may readily be repeated by dissolving alum, sugar, and similar substances, and crystallizing them on glass, or a string placed in the solution, and allowed to remain undisturbed. Bouquets of crystallized grasses are made in this way, often being colored afterward.
Almost all mineral substances can be crystallized, and some of the finest observations of the microscopist are made upon these objects.