WATER is one of the most widely diffused bodies in nature, about three-fourths of the surface of the globe being covered by it. The benevolence of the Creator is manifest in the wide diffusion of this element. It is indispensable both to the animal and to the vegetable worlds. It serves invaluable purposes in the arts and manufactures; in the form of rivers, lakes, and seas, it becomes a medium of intercourse among the nations of the Earth. To the vast reservoir of water in the ocean, moreover, we are indebted for the clouds, which carry moisture from the sea and let it down upon the parched and thirsty earth in refreshing rain.
There is a river in the sky a hundred times larger than theAmazon or the Mississippi;and not only one, but many.
These rivers come to us in the spring rains, the summer showers, the nightly dews, and the winter snows. The water which thus falls from the sky every year would cover the earth, if it were level like a field, to the depth of fully five feet.
All the waters of our mighty rivers and lakes were once clouds, and the clouds are but vapour lifted into the sky from the sea by the secret engineering of the sun. The winds, by the flapping of their mighty wings, drive the vapour over the land to the hills, and the mountains, and the thirsty fields; and there the clouds pour their blessings on the farms, and pastures, and orchards, and the dusty roads and the wayside grass, bringing greenness and gladness everywhere.
The sea is in the sparkling dew-drop, and it falls in the summer shower. It makes the grass grow and the flowers unfoldtheir gay banners-red, white and blue. It ripens the peach and the apple, and loads the fields with the yellow harvest. It spins our thread and weaves our cloth. It is harnessed to mighty engines, and does more work than thousands of men and horses. It saws our timber, lifts our coal from the bowels of the earth, and steams in the iron horse. The sea clothes and cools us, and carries us and works for us. All the water in our rivers, lakes, fountains, in the dew, fog, snow, sleet, and rain, comes alike from the sea.
From whatever source water is procured, whether from ocean, river, lake, or spring, it is always the same. It is true that water from the sea has a different taste from that of rain or river water; but the difference does not lie in the water, but in the substances dissolved in it.
Water is composed of two gases, oxygen and hydrogen, in the proportion of eight parts of oxygen to one of hydrogen, byweight.
It is one of the most marvellous facts in the naturalworld, that though hydrogen is highly inflammable, and oxygen is a supporter of combustion, both combined form an element destructive to fire.
Pure water is destitute of colour, taste, and smell. It seldom, however, occurs in this state, but usually contains various ingredients, derived either from the atmosphere or from the earth. Rain water is the purest that can be obtained, except by distillation.The waters of the globe are divided into fresh and salt. The fresh water includes all streams and rivers, and nearly all the springs and the greater number of the lakes, on the Earth"s surface. They are called fresh, because they contain no amount of saline matter unfitting them for use. It is supposed that thelakes of North America contain more than half of all the fresh water on the face of the globe.
Salt water is that which fills the vast basin of the ocean, besides numerous lakes and springs. It forms much the larger portion of the liquid element. The proportion of saline matter which the ocean contains is about three and a half per cent. Supposing the sea to have a mean depth of one thousand feet, it has been calculated that the amount of common salt it contains is equal to five times the mass of the Alps, or about one-third less than that of the Himalayah Mountains!
Near the equator and towards the poles the ocean is less saltthan in other parts. This is probably owing to the abundant rains at the equator, and to the melting of the ice in in the polar regions.
The saline ingredients render sea water much heavier than fresh water, and, consequently, better adapted for navigation. Fresh water freezes at the temperature of 32 degrees; saltwater, at that of 281/2 degrees. The healthfulness of the oceanis partly ascribed to its constant motion, which prevents its waters from becoming stagnant and corrupt.
