Nikola Tesla and His Works - On the Occassion of the Eightieth Anniversary Page 15

this work was greatly hindered by the fire that completely destroyed the six-story building at South Five Avenue № 33-35 on March 13, 1895, in which Tesla occupied the entire fourth floor. That’s when Tesla’s entire laboratory burned down, with all the instruments and devices and with all the files and plans about the work started. After this, Tesla returned again in 1896 to experiments on wireless transmission. In the same year, in new laboratories in New York, he managed to transmit wireless signals over a distance of 20 miles (about 32 km) [14]. In 1898, he built a ship, especially for experimentation, launched it into the sea near New York and steered it, without wires, from the shore. He protected the results obtained in the above works with patents no. 654 576, 649 621 of September 2, 1897. and no. 613 809 of July 1, 1898. Among these patent no. 649 621 has special importance. In it, Tesla pointed out that for good transmission results, it is necessary to achieve resonance between the primary and secondary circuits on the sender and the receiver, as well as resonance between the secondary circuit of the sender and the primary circuit of the receiver (Tesla’ four tuned circuits).

In 1899, Tesla conducted large-scale experiments with wireless signal transmission. In the State of Colorado, he built a large transmitting station and, at a distance of 600 miles (about 1000 km) from it, a large receiving station. Between these stations