<!-- Any copyright is dedicated to the Public Domain. http://creativecommons.org/licenses/publicdomain/ --> <html> <body> <input type="text"/> <div style="width:100px; height:100px; overflow:scroll;"> In 1629, Isaac Beeckman proposed an experiment in which a person would observe the flash of a cannon reflecting off a mirror about one mile (1.6 km) away. </div> </body> </html>