听力原文：Everyone has heard of the Braille system of reading for the blind. But few people know why it is called the 'Braille' system or who Louis Braille was. In the year 1812,Louis Braille was a very small boy. He lived in a small town in France. Louis' father had a small shop in which he made things of leather. One day Louis was playing in his father's shop and picked up a small tool with a very sharp point, Louis fell, the point of the tool entered his eye. And later he became blind in both eyes. One day, he said to his father,' Blind people are the loneliest people in the world. I can tell one bird from another by its sound. I can know the door of the house by feeling it with my hand. But there are so many things which I can not hear and can not feel. Only books can free the blind. But there are no books for us to read.'
Why is the reading system for the blind called the Braille?