书城英文图书英国学生文学读本(套装共6册)
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第240章 MEASUREMENT OF TIME

1.How did men first measure time?We can pictureto ourselves how our ancestorsturned their eyesin wonder to the great sun;how they watched himrising higher and highertill he reached his noondaystrength,then sinking lower and lower until he disappeared beneath the western horizon and left the world to darkness.

2.The great sun has sunk to rest,and in his place have come the gentle moon and thousands of twinkling stars.But again the sun rises,shines,and sets.Again he is followed by moon and stars.Man‘s first lesson in time has now been learned:the light he calls day,the darkness night.

3.Of all the heavenly bodies,the moon is the only one that seems to change its form and size.At one timeit is a mere crescent,at another it is a full circle.Mancounts the days from new moon to new moon,or from full moon to full moon,and calls the period a month.This is the second step in counting time.

4.He next observes changes in the length of the days and in the heat of the sun.He sees the flowers spring up,blossom,and decay,and the trees put on their gay garments of green,change them to sober brown,and finally lose them altogether.His ideas of seed-time,harvest,and winter are formed,and he begins to count the moons from seed-time to seed-time,or from winter to winter,and makes the grand discovery-“Twelve months make one year.”In such a way as this men got their first notions of year,and month,and day.

5.Hundreds of years seem to have passed before hours,minutes,and seconds werethought of.Fora long time morning,noon,and evening were the only divisions of the day.The night was divided into two orthree “watches.”It must have been noticed very earlythat the shadows of trees,posts,and other objects fell in the same direction at the same time every day.Fromthis was invented the sun-dial;but it told the timeonly when the sun shone,and was useless in cloudyweather or at night.

6.A great improvement was made when water-clocks and sand-clocks were invented.In the one so much water,and in the other so much sand,dropped in a given time from a higher to a lower vessel.The water-clockwas used for periods of about twelve hours;the sand-clock was used for one hour,and was therefore called an “hour-glass.”Sometimes people carried hour-glasses with them,as we carry watches.

7.King Alfred of England was one of the busiest of men,and knew how precious time was.He invented a new way of measuring it.He ordered six candles of equal weight and length to be made out of a certain quantity of wax.Each candle was divided into twelve inches,and each inch intotwelve parts.As each candle burned four hours,the six candles lasted twenty-four hours.The king keptsuch candles burning night and day wherever he went.As the candies burned one inch in twenty minutes,and three-twelfths of an inch in five minutes,Alfred was able todo what no one before his day had done-to measure a very short space of time.

8.But the wind blew through the walls of His palaces,the windows of his churches,and the canvas of his tents,and the candles sometimes burned away at an irregular rate,andsometimes were put out altogether.So Alfred made lanterns of wood with verythin plates of horn for the sides.Thus sheltered,his candles became more trustworthy time keepers.

9.The first clock with weights and wheels is said to have been invented about the year 1000A.D.;but clocks of that kind could not be carried about from place to place.Other four hundred and fifty years passed away before the first watch was made at Nu-remberg in Germany.As the works were shut up inround metal cases,these early watches were often called “Nuremberg eggs.”The cases afterwards came to be made of many different shapes and sizes,and they were often ornamented with crystal and precious stones,as well as with gold and silver.