Reference has already been made to the callers upon Edison; and to give simply the names of persons of distinction would fill many pages of this record. Some were mere consumers of time; others were gladly welcomed, like Lord Kelvin, the greatest physicist of the last century, with whom Edison was always in friendly communication. "The first time I saw Lord Kelvin, he came to my laboratory at Menlo Park in 1876." (He reported most favorably on Edison's automatic telegraph system at the Philadelphia Exposition of 1876.) "I was then experimenting with sending eight messages simultaneously over a wire by means of synchronizing tuning-forks. I would take a wire with similar apparatus at both ends, and would throw it over on one set of instruments, take it away, and get it back so quickly that you would not miss it, thereby taking advantage of the rapidity of electricity to perform operations. On my local wire I got it to work very nicely. When Sir William Thomson (Kelvin) came in the room, he was introduced to me, and had a number of friends with him. He said: `What have you here?' I told him briefly what it was. He then turned around, and to my great surprise explained the whole thing to his friends. Quite a different exhibition was given two weeks later by another well-known Englishman, also an electrician, who came in with his friends, and I was trying for two hours to explain it to him and failed."