In the exhibition hall of the Museum of Chinese History in Beijing,there is a restored model of the first seismograph.The inventor was Zhang Heng,a famous scientist in the Eastern Han Dynasty.In 132 A.D,in the then national capital Luoyang,Zhang Heng made the ancient seismograph to identify the direction of an earthquake.It was made of fine copper,and looked like a big cup with a lid.The instrument was cast with eight dragons on the surface,and each dragon held a copper ball in the mouth.On the ground below the dragons,there were eight copper toads raising their heads and opening their mouths opposite the dragons'mouths.People highly respect Zhang Heng as a great scientist,and they often hold commemorative activities to show respect for him.A crater on the moon was named after him.

　　算盤(abacus)是中國傳統的計算工具，也是中國古代的一項重大發明。阿拉伯數字出現以前，算盤在世界各地廣泛使用。算盤是矩形的木框，木框上固定著帶算珠的木桿。木框中間的橫梁(beam)將木桿分成兩部分：木桿上方的兩顆算珠 (counting beads)每個代表5,下方的五顆算珠每個代表1。隨著算盤的應用，人們總結出很多計算技巧，提高了計算速度。由于算盤易于制造，而且計算口訣易于記憶和操作，因此算盤在中國十分流行。

　　As a traditional Chinese calculation tool and an important ancient Chinese invention,the abacus was widely used before the invention of Arabic numerals in the world. The abacus is a rectangle with a wooden frame. Within the frame,rods with stringed beads are fixed. The beam in the middle of the frame divides each rod into two parts. The two counting beads in the upper part of each rod represent five and the rest five beads in the lower part represent one. With the application of the abacus, people summarized many calculation tips to help improve the speed of calculation. As the abacus is simple to produce, and its calculation tips are easy to memorize and operate, it is quite popular in China.

　　印刷術發明之前，想出版新書的學者必須一字一字地抄寫。北宋時期，經過多年的實驗，畢昇發明了活字印刷術(movable-type printing)。他把漢字刻在一小塊泥胚(pieces of clay)上，加熱漢字直到其變成硬的活字。印書時,人們按順序將活字擺在一起，印出印跡。印刷完后，他們把字分開，以后重復使用。這種方法既經濟又省時。中國的活字印刷術首先向東傳至朝鮮和日本，之后向西傳至波斯(Persia)和埃及，最后傳遍全球。活字印刷術的發明大大促進了世界各國的文化交流。

　　Before printing was invented，a scholar had to copycharacters one by one if he wanted to publish a newbook.During the Northern Song Dynasty, Bi Shenginvented the movable-type printing after many yearsof experimentation.He engraved the characters onsmall pieces of clay,and heated them until they became hard movable characters.When printinga book，people placed the moveable characters in order into a whole block and then ran off aprint.After printing, they took the block apart and reused the characters later.This method wasboth economical and time-saving.China's movable-type printing first spread eastward intoKorea and Japan,then westward into Persia and Egypt,and at last,around the world.Theinvention of movable-type printing greatly promoted the cultural exchanges among countriesall over the world.