Tesla Patents Expire (May 15, 1905)

Inventor's Rights to Alternating Current Discoveries Now Public Property — Owners Will Fight.

It was announced to-day that the famous patents, of Nikola Tesla covering the alternating current motor, in use in all large power plants throughout the world, have expired. The patents referred to are those known' in the electrical profession as the "three fundamental patents." The expiration of the patent rights is an event of fully as great importance as the expiration of those which protects the Bell telephone.

The royalties on these patents have been for many years the source of the noted inventor's Income. It is impossible to say how much they have brought him, but they have made him a wealthy man and enabled him to maintain his magnificent electrica! laboratory and to prosecute his studies inte the subject of wireless telegraphy.

In 1885, Professor Galileo Ferriaris of Turin, Italy, discovered the rotating field of the electro magnet, and made practical application of his discovery. In 1888 Tesla received from the United States patents covering the broad application of the principles, George Westinghouse bought the patent rights of Ferraris as well as Tesla's.

"The fundamental patents" have been for: years in the possession of the so called "Patent Pool Trust." Many efforts have been made to break them down without success. Now that the seventeen year period or. the patents has expired, the Westinghouse people announce susidiary patents and its determination to fight infringements.