The American De Forest Wireless Telegraph Company has developed from the inventions of Dr. Lee de Forest, a young Yale graduate. His system differs from that of Marconi chiefly in the receiver. At first an instrument called the "anti-coherer," or "responder," was used in place of the coherer. The action of this instrument was just the reverse of the coherer, that is, a good path was normally provided for the local circuit, but this path was broken by the electric oscillations in the antenna. The anti-coherer was later replaced by another instrument, which acts electrolytically to a large extent. This instrument, like the coherer, normally offers a resistance to the current in the local circuit, but this resistance is broken down by the electric oscillations in the antenna. Another difference between the systems lies in the fact that the De Forest company uses a telephone receiver in the local circuit instead of the telegraph receiver for receiving the signals. Signals by the De Forest system can be transmitted at the rate of twenty-five to thirty words per minute. The De Forest Company has established a score of stations along the Atlantic coast, and several along the Great Lakes. Late in 1903 the De Forest Company entered into a contract with the London "Times" to furnish news of the Russo-Japanese war. The steamer "Haimun" was equipped with wireless telegraph apparatus, and rendered valuable service in reporting naval operations and engagements. These reports were sent by wireless telegraphy to Wei-hai-Wei and thence by cable to London. In July, 1904, the United States Government closed a contract with the De Forest Company for a series of stations in the West Indies and Panama. These, it is stated, are to form links in a chain of De Forest stations which will connect New England with Japan, China and the Philippines. The chain is to follow the Atlantic coast to Key West, and thence run via Porto Rico to Panama. From Panama it will follow the Pacific coast to Seattle, thence via the Aleutian Islands to Japan, Wei-hai-Wei, China and the Philippines, returning to San Francisco through Guam and Hawaii. Under the terms of the contract, commercial messages are to be interchangeable between all stations equipped with the De Forest system, whether operated by the Government or the De Forest Company.

The following is a list of wireless telegraph stations, equipped with De Forest apparatus, and now complete and in operation for the transmission of wireless messages:

The following steamers are equipped with De Forest apparatus:

The following De Forest stations have been erected or are in course of erection:

Steamers

Six vessels of the United States Navy.