Sir Isaac Newton measured the speed of sound in a corridor at Cambridge University in England. He stamped his foot at one end of the corridor and timed the interval until he heard the echo from the other end of the hall. Knowing the length of the hall, Newton computed the speed of sound. Important as traffic laws and their enforcement are, many people think that laws can prevent only a relatively small percentage of highway accidents. A very secure form of communication is furnished by wires, but it requires time to set up the wires, and they can get out of order.
Telephone lines involve a great deal of maintenance.
Justinian I lives in history as the Roman Emperor responsible for gathering Roman law into a single code, or body, of law. Justinian's code is a significant part of many modern systems of law. Edward I, a king of England during the Middle Ages, is known as the English Justinian. The way a person walks may give clues to personal traits. The person who walks with a careless shuffle is likely to be judged careless and unreliable.