detection than anything else. His hunch was right, but it was not until five years later that he was able to get together the few dollars necessary for him to work out his idea. The vacuum tube was the result.

During the Chicago period the most money that De Forest earned was ten dollars a week. In off hours he worked as an assistant in the laboratory of the Armour Institute. For this he received no pay, but he was allowed the use of the laboratory. This was some help to him, but not much. He was doing pioneer work, and the laboratories of those days contained little that could help him. Some idea of his struggles at this time is found in a letter he wrote to a friend.

"It's a great life I'm leading now," he wrote. "Here, one does not lose caste by leaving off his cuffs, by wearing a collar for a week, or a shirt even longer. If you go unshaved, you simply pass for a ‘single taxer' and are given free range at the lunch counter. My pants are getting thinner every day, and my coat is perfumed with fried potatoes of the Comet lunchroom. Sometimes I have ten cents in hand, sometimes twice that sum.

In 1901, when he thought he had his apparatus fairly well perfected, came the international yacht races, bringing-as it then seemed the failure of all his hopes. But the experience was of some help to

him, and a former classmate invested a thousand dollars, for which he received one third of the stock of the newly incorporated De Forest Wireless Telegraph Company. A few years ago, when De Forest sold his patent rights and licenses, a one-third interest was worth $300,000.

He was sure, by now, that he had reached his goal, and that it only remained to get capital enough to put his invention on the market. The classmate, who was now a one-third owner of the business, suggested that this might be accomplished more easily if demonstrating stations were put up, so that prospective investors could see for themselves the practical value of wireless. De Forest accordingly built a transmitting set in the shop in Jersey City, while his friend secured permission to install the receiving station in the dome of the Manhattan Life Building, in New York.

The attempt added another failure to De Forest's long list. The system; refused to work! The signals did not come through! It was months before De Forest learned enough of radio to know why he had failed. The great dome, covered with copper, absorbed the energy of the signals. There was nothing left for the receiver.

A short time later the transmitting station was moved to State Street, in New York, with the receiv ing station in the old Castleton Hotel, on Staten

Island. This time conditions were more favorable, and the apparatus performed better.

At that time the late George Westinghouse was the outstanding figure in the electrical world.

He had

used the immense fortune derived from his invention of the air brake to found the Westinghouse Electric and Manufacturing Company, one of the largest corporations in its field.

Two of De Forest's associates had tried to interest Westinghouse in wireless telegraphy, and De Forest awaited his visit with intense anxiety.

Westinghouse was a big man, with great natural dignity of manner," De Forest told me. "I was so much in awe of him that, beyond shaking hands and mumbling a few confused words, I said nothing to him the whole time he was in the station.

"We sent several messages to the Staten Island receiving station, and the tests were fairly successful. "Westinghouse maintained noncommittal silence throughout the demonstration and when we had finished be simply left, without saying anything, one way or the other. Finally, however, he sent me his verdict: He was not interested!"'

Nineteen years later the Westinghouse company opened broadcasting station KDKA, the first of the big Eastern stations. This marked the beginning of the immense interest which has, in a little more than

two years, swept the country from end to end and made the radio receiving set known to millions..

After his failure to interest Westinghouse, De Forest continued to perfect his apparatus. His greatest difficulty now was in convincing people that wireless was anything more than an interesting scientific toy.

In January, 1904, he set up two transmitting stations at the Louisiana Purchase Centennial Exposition, at St. Louis, with receiving stations at Chicago and Springfield, Illinois. These were tested out by the Jury of Awards, with every precaution against fraud. Everything worked perfectly. It was the longest distance that messages ever had been transmitted over land by wireless, up to that time. De Forest sent messages for people who had friends in Springfield and Chicago, and these messages were exhibited as great curiosities.

At the end of the exposition he was awarded the gold medal, diploma, and the first prize over two competitors, Marconi and the German Telefunken system.

All this time he never had lost sight of his old idea of a "heated gas" detector. And now, for the first time, he was able to go ahead with his experiments on a substantial scale. He soon reached the conclusion that although a flame detector, on the order of the

Welsbach burner, was perfectly possible, it was impractical because of the difficulty of carrying a supply of gas; so he turned to the idea of heating the gas in a closed glass tube by means of an electric filament. In 1905 he discovered the principle of the "audion" vacuum tube that is in general use to-day. It was patented in 1907.

In 1906, he began working on the idea of transmitting the voice by wireless. It had been discovered that the flame of an arc light could be used to produce radio waves, and that these waves would carry the human voice.

In that year the yacht "Thelma," belonging to W. R. Huntington, of Elyria, Ohio, was equipped with a radiophone for the purpose of reporting the yacht races at Put-in-Bay on the Great Lakes. It was the first vessel to be thus equipped. The transmission of voice and phonograph music was entirely successful, and this was the end of skepticism as to the practicability and value of radio. The successful equipment of the "Thelma" brought an order from Uncle Sam to install radiophones on the ships of the Atlantic Squadron, then under the command of Admiral "Fighting Bob" Evans.

Most of the millions of broadcast listeners in the United States heard broadcasting for the first time in 1921. Few had heard it, or even heard of it, before