Mr Swift chuckled silently, gradually breaking into a louder laugh. Instead of being angry, Tom only regarded his father with an indulgent smile, and continued:
"All right, Dad. Go ahead, laugh!"
"Well, Tom, I'm not exactly laughing at you—it's more at the idea than anything else. The idea of talking over a wire and, at the same time, having light waves, as well as electrical waves passing on the same conductor!"
"All right, Dad, go ahead and laugh. I don't mind," said Tom, good-naturedly. "Folks laughed at Bell, when he said he could send a human voice over a copper string; but Bell went ahead and to-day we can talk over a thousand miles by wire. That was the telephone.
"Folks laughed at Morse when he said he could send a message over the wire. He let 'em laugh, but we have the telegraph. Folks laughed at Edison, when he said he could take the human voice—or any other sound—and fix it on a wax cylinder or a hard-rubber plate—but he did it, and we have the phonograph. And folks laughed at Santos Dumont, at the Wrights, and at all the other fellows, who said they could take a heavier-than-air machine, and skim above the clouds like a bird; but we do it—I've done it—you've done it.
