400

INVENTIONS OF NIKOLA TESLA.

more sharply defined; but I have not noted that, generally speak-ing, the circles induced were very sharply defined, as Prof. J. J.Thomson has observed; on the contrary, in my experiments theywere broad and often the whole of the bulb or tube was illumi-nated ; and in one case I have observed an intensely purplish

Fig. 214.

■■ P

glow, to which Prof. J. J. Thomson refers. But the circles werealways in close proximity to the primary and were considerablyeasier produced when the latter was very close to the glass, muchmore so than would be expected assuming the action to be elee-

Fig. 215.

tromagnetic and considering the distance; and these facts speakfor an electrostatic effect.

Furthermore I have observed that there is a molecular bom-bardment in the plane of the luminous circle at right angles tothe glass—supposing the circle to be in the plane of the primary