Two smaller images expand this theme of physics in its theoretical and practical incarnations. The electromagnet depicted here was used most famously and extensively by Michael Faraday. With it, he demonstrated the conversion of electricity and magnetism and led the way to understanding the relationships among many basic forces of nature and eventually to the concepts of energy and field. It too, was iconic and emblematic in its day and stimulated many useful inventions. Electromagnets too are our invisible companions in daily life.