The compass(罗盘) is a device that is absolutely necessary for the【56】of ships and airplanes．Hikers often need a compass, too．Anyone who does not use 【57】roads should have a compass.
A compass will always 【58】to know your direction．If you have a map【59】land marks such as roads, mountains, rivers, and lakes, you can immediately find out where you are．The compass 【60】you to place your map in an 【61】position according to the directions．You can then 【62】 where you are with points on the map.
The Chinese were the first people 【63】 the magnet(磁铁)【】a compass．They first used compasses to 【65】their ships between the years 100 B．C．and A.D．100．their compasses were and 【66】devices.【67】The magnetic iron into their compass, these early seamen placed the magnet on a cork or a piece of straw．They then put the iron-cork system in a bowl of water, the【68】magnet turned easily, aligning(排成列) itself with the directions north and【69】．
Later the Chinese invention was put together【70】a Babylonian invention, the degree．Then the compass became 【71】．Compasses 【72】well on wooden ships.【73】, when metal ships appeared in the 1800s, the magnetic compass was【74】．the metal in the ship【75】the magnet．Modem ships now use the gyrocompass and the radio compass for navigation.
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