In November, 1875, he discovered that the vibrations created in a reed by the voice could be transmitted so as to reproduce words and sounds. One day in January, 1876, he called a dozen of the pupils at Monroe's school into his room and exhibited an apparatus by which singing was more or less satisfactorily transmitted by wire from the cellar of the building to a room on the fourth floor. The exhibition created a sensation among the pupils, but, although no attempts were made by Bell to conceal what he was doing, or how he did it, the noise of his discovery does not seem to have reached the outside world. With an old cigar-box, two hundred feet of wire, two magnets from a toy fish-pond, the first Bell telephone was brought into existence. The apparatus was, however, not yet the practical telephone as we know it, but it was sufficient of a curiosity to warrant its exhibition in an improved form at the Centennial Exhibition, when Sir William Thomson spoke of it as "perhaps the greatest marvel hitherto achieved by the electric telegraph." The next year Bell succeeded in bringing the telephone to the condition in which it became of immediate practical value. Strange to say, the public was at first slow to appreciate the great importance of the invention, and when Bell took it to England, in 1877, he could find no purchaser for half the European rights at $10,000. In this country, thanks to the business energy of Professor Gardiner Hubbard, of Harvard, Bell's father-in-law, the telephone was soon made commercially valuable, and there are now said to be nearly six hundred thousand telephones in use in the United States alone. Professor Bell, as may be imagined, is not idle. His vast fortune has enabled him to continue costly experiments in aiding deaf and dumb people, and it will probably be in this field that his next achievement will be made. Personally, he is a reserved and thoughtful man, wholly given up to his scientific work. His wife, whom he married in 1876, was one of his deaf and dumb pupils. It is often said that it was largely due to his intense desire to soften her misfortune that his experiments were so exhaustive and finally became so productive in another direction. His home life in Washington, where he bought, in 1885, the superb house on Scott Circle known as "Broadhead's Folly," after the man who built it and ruined himself in so doing, is said to be an ideally peaceful and happy one, given up to study and efforts to alleviate the troubles of the deaf and dumb.