Early one morning, more than a hundred years ago, an American inventor called Elias Howe finally fell asleep. He had been working all night on the design of a sewing machine but he had run into a very difficult problem: It seemed impossible to get the thread to run smoothly around the needle. Though he was tired, Howe slept badly. He turned and turned. Then he had a dream. He dreamt that he had been caught by terrible savages whose king wanted to kill him and eat him unless he could build a perfect sewing machine. When he tried to do so, Howe ran into the same problem as before. The thread kept getting caught around the needle. The king flew into the cage and ordered his soldiers to kill Howe. They came up towards him with their spears raised. But suddenly the inventor noticed something. There was a hole in the tip of each spear. The inventor awoke from the dream, realizing that he had just found the answer to the problem. Instead of trying to get the thread to run around the needle, he should make it run through a small hole in the center of the needle. This was the simple idea that finally made Howe design and build the first really practised sewing machine. Elias Howe was not the only one in finding the answer to his problem in this way. Thomas Edison, the inventor of the electric light, said his best ideas came into him in dreams. So did the great physicist Albert Einstein. Charlotte Bronte also drew in her dreams in writing Jane Eyre. To know the value of dreams, you have to understand what happens when you are asleep. Even then, a part of your mind is still working. This unconscious( 无意识的 ), but still active part understands your experiences and goes to work on the problems you have had during the day. It stores all sorts of information that you may have forgotten or never have really noticed. It is only when you fall asleep that this part of the brain can send messages to the part you use when you are awake. However, the unconscious part acts in a special way. It uses strange images which the conscious part may not understand at first. This is why dreams are sometimes called “secret messages to ourselves”.