484

INVENTIONS OB 1 NIKOLA TESLA.

development chiefly interesting as showing Mr. Tesla’s efforts toadapt liis system to the existing high frequencies.

On the right side of the table, at s, t, are shown, on separatesupports, larger and more perfected armatures of commercialmotors, and in the space around the table a variety of motors andgenerators supplying currents to them was exhibited.

The high frequency exhibit embraced Mr. Tesla’s first originalapparatus used in his investigations. There was exhibited aglass tube with one layer of silk-covered wire wound at the topand a copper ribbon on the inside. This was the first disruptivedischarge coil constructed by him. At u is shown the disruptive

Fig. 311.

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discharge coil exhibited by him in his lecture before the Ameri-can Institute of Electrical Engineers, in May, 1891. 1 At v and ware shown some of the first high frequency transformers. Anumber of various fields and armatures of small models of highfrequency apparatus as shown at x and y, and others not visiblein the picture, were exhibited. In the annexed space the dynamothen used by Mr. Tesla at Columbia College was exhibited ; alsoanother form of high frequency dynamo used.

In this space also was arranged a battery of Leyden jars andhis large disruptive discharge coil which was used for exhibiting

1. See Part II, Ohap. XXVI., page 145.