C No one knows when the first kite was made. The first record of a kite was more than 2,000 years ago in China. Han Xin, the leader of an army, wanted to bring down a king. He decided to dig a tunnel (隊道)into the king’s palace. He flew a kite over the wall of the palace to make sure the length (长度)of its string (线).In this way, he could determine how long the tunnel should be.His men in the tunnel took the kite string with them. When they reached the end of the string, they knew to dig up. Kites have been flown in Japan for hundreds of years. In the 1700s, kites were flown in autumn to give thanks for a good harvest. They were also flown to send good wishes to couples who had their first son. Today in Japan, kites are often flown as part of a celebration, such as the beginning of a new year. And kite festivals are held each year in many parts of the country. Kites have been used for scientific purposes in the western world. In 1752,Benjamin Franklin tied a key to a kite and flew it in a storm to find out that lightening was a form of electricity. In the 1890s,Lawrence Hargrave invented the box kite to test ideas about flight. From 1898 until 1933,the United States Weather Bureau (气象局) used box kites to collect weather data. The Wright brothers also experimented (试验)with kites. What they learnt helped them make the first airplane flight in 1903.