There was a time--and that not so very long ago--when it was thought impossible that a man should ever be able to speak clearly and distinctly to a friend a {265} hundred miles away, and hear in return, as clearly and as distinctly, the voice of his friend. Certain men, however, who were prying into the secrets of nature discovered some things about sound. They learned that sound travels through some medium, like the air, by means of waves--waves of alternate condensation and rarefaction of the air, for example. Then these men studied the human ear, and they learned that as these sound waves struck the ear, the drum of the ear was made to vibrate back and forth as a condensed part of the air or a rarefied part of the air struck it. The men became interested; further study revealed the fact that almost any disk, like the drum of the ear, could be made to vibrate to sound waves. It was found that these sound waves could be transmitted through string, or wire. It was discovered that a small current of electricity flowing through a wire aided in the conducting of the sound wave. Little by little science progressed, until by and by there appeared a telephone. It was crude, and it reproduced the human voice with a terrible roar. But the men of science worked at it; they perfected first one part of it, then another, as they learned better to understand the laws governing the reproduction of sound. Finally came the perfect telephone. Today it is possible to telephone--not a hundred miles merely--but from New York to San Francisco, clear across a continent, a distance of several thousand miles. Such an achievement, if it had been shown suddenly, would have been considered a miracle. It would have been in violation of all the known laws of nature. But now we know that this {266} miracle has been accomplished through the harnessing of natural laws not known to our forefathers. The achievement is the result of neither violation of law, nor co-operation with Beelzebub. [Sidenote: Other miracles of science.]