The Internet Archive discovers and captures web pages through many different web crawls. At any given time several distinct crawls are running, some for months, and some every day or longer. View the web archive through the Wayback Machine.
books.google.com - Light and sound have been studied for a long time. With that knowledge, people have created such important things as telescopes, microscopes, cameras, telephones, radio, television, tape recorders, lasers, compact discs, and MP3 players. For more information on light and sound, read All About Light and...https://books.google.com/books/about/Pioneers_of_Light_and_Sound.html?id=Wp6E3y-58LkC&utm_source=gb-gplus-sharePioneers of Light and Sound