Icebergs
[size=3][color=#29384e][font=Times New Roman]Icebergs are among nature[/font][font=宋体]‘[/font][font=Times New Roman]s most spectacular creations[/font][font=宋体]，[/font][font=Times New Roman] and yet most people have never seen one. A vague air of mystery envelops them. They come into being [/font][font=宋体]——[/font][font=Times New Roman] somewhere [/font][font=宋体]——[/font][font=Times New Roman]in faraway[/font][font=宋体]，[/font][font=Times New Roman] frigid waters[/font][font=宋体]，[/font][font=Times New Roman] amid thunderous noise and splashing turbulence[/font][font=宋体]，[/font][font=Times New Roman] which in most cases no one hears or sees. They exist only a short time and then slowly waste away just as unnoticed.[/font][/color][/size][size=3][color=#29384e][font=Times New Roman] [/font][/color][/size]
[size=3][color=#29384e][font=宋体] [/font][font=Times New Roman]Objects of sheerest beauty they have been called. Appearing in an endless variety of shapes[/font][font=宋体]，[/font][font=Times New Roman] they may be dazzlingly white[/font][font=宋体]，[/font][font=Times New Roman] or they may be glassy blue[/font][font=宋体]，[/font][font=Times New Roman] green or purple[/font][font=宋体]，[/font][font=Times New Roman] tinted faintly of in darker hues. They are graceful[/font][font=宋体]，[/font][font=Times New Roman] stately[/font][font=宋体]，[/font][font=Times New Roman] inspiring [/font][font=宋体]——[/font][font=Times New Roman] in calm[/font][font=宋体]，[/font][font=Times New Roman] sunlight seas.[/font][/color][/size]
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[size=3][color=#29384e][font=宋体] [/font][font=Times New Roman]But they are also called frightening and dangerous[/font][font=宋体]，[/font][font=Times New Roman] and that they are [/font][font=宋体]——[/font][font=Times New Roman] in the night[/font][font=宋体]，[/font][font=Times New Roman] in the fog[/font][font=宋体]，[/font][font=Times New Roman] and in storms. Even in clear weather one is wise to stay a safe distance away from them. Most of their bulk is hidden below the water[/font][font=宋体]，[/font][font=Times New Roman] so their underwater parts may extend out far beyond the visible top. Also[/font][font=宋体]，[/font][font=Times New Roman] they may roll over unexpectedly[/font][font=宋体]，[/font][font=Times New Roman] churning the waters around them.[/font][/color][/size]
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[size=3][color=#29384e][font=宋体] [/font][font=Times New Roman]Icebergs are parts of glaciers that break off[/font][font=宋体]，[/font][font=Times New Roman] drift into the water[/font][font=宋体]，[/font][font=Times New Roman] float about awhile[/font][font=宋体]，[/font][font=Times New Roman] and finally melt. Icebergs afloat today are made of snowflakes that have fallen over long ages of time. They embody snows that drifted down hundreds[/font][font=宋体]，[/font][font=Times New Roman] or many thousands[/font][font=宋体]，[/font][font=Times New Roman] or in some cases maybe a million years ago. The snows fell in polar regions and on cold mountains[/font][font=宋体]，[/font][font=Times New Roman] where they melted only a little or not at all[/font][font=宋体]，[/font][font=Times New Roman] and so collected to great depths over the years and centuries.[/font][/color][/size]
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[color=#29384e][font=宋体][size=10.5pt] [/size][/font][size=10.5pt]As each year[/size][font=宋体][size=10.5pt]‘[/size][/font][size=10.5pt]s snow accumulation lay on the surface[/size][font=宋体][size=10.5pt]，[/size][/font][size=10.5pt] evaporation and melting caused the snowflakes slowly to lose their feathery points and become tiny grains of ice. When new snow fell on top of the old[/size][font=宋体][size=10.5pt]，[/size][/font][size=10.5pt] it too turned to icy grains. So blankets of snow and ice grains mounted layer upon layer and were of such great thickness that the weight of the upper layers compressed the lower ones. With time and pressure from above[/size][font=宋体][size=10.5pt]，[/size][/font][size=10.5pt] the many small ice grains joined and changed to larger crystals[/size][font=宋体][size=10.5pt]，[/size][/font][size=10.5pt] and eventually the deeper crystals merged into a solid mass of ice.[/size][/color]
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