Tesla noticed that white corona sheaths were actually covering the outer cylinder wall at times. These would appear, build in strength, and disappear on sudden discharge with a surprising length. The sheathing action was repetitive when the cylinder had a critically small volume. Very small cylinders behaved like rods, where discharges only appeared at their edges. The stability of these strange sheath discharges varied with cylinder diameter and length.

Tesla noticed that not every cylinder performed well near the impulser. Only cylinders of specific volume produced stable and continuous white electrical sheaths. If the cylinders were too small; then the sheaths were intermittent and unstable. There was an obvious connection between the supplied impulse train and the cylinder volume. But what was it?

Tesla surveyed the entire range of his recent discoveries. Impulses produced a radiant electrical effect. Radiant electricity, was mysteriously flowing through space. As it flowed, it focused over metal conductors as a white fluidic corona. When the shape and volume of the metal conductors were just right, the energy appeared as a stable white corona of far greater voltage than the impulse generator supplied. More questions. More discoveries.

Rods produced sparks from their edges, but not as long as copper cylinders did. Tesla selected a cylinder which worked very well, and placed several horizontal “cuts” all around its surface. He was totally surprised when, on testing, the spark discharge from the cut cylinder was notably larger than before. Increased spark length means increased voltage. But why did this diminished conductivity force the voltage up?

The cuts diminished conductivity in the cylinder by forcing the energy into a tighter “squeeze”. He had noted that electrical impulses displayed a tendency to traverse the outer surface of metal conductors. Certain cylinders were often ensheathed in a fluidic white discharge which smoothly traveled between coil ends in a tightly constricted layer. Here was something truly notable. His input voltage was far less than that produced from the upper coil terminal. But why from end to end?

The essential reason why current preferred outer surface conduction was precisely because they were impulsing. The sudden shock which any conductor experienced produced an expansive effect, where the electrical charge was rejected by the conductive interior. This “skin effect” was a function of impulse time and conductor resistance. Highly resistant objects forced all of the impulse energy to the surface.

Now he was getting somewhere. Frustrated radiant electricity constricted into a tighter surface volume when encountering metal surfaces. This intense surface focusing effect brought the voltage up to tremendous values. Here was a new transformer effect! He believed it was an electrostatic transformation. Impulse currents each possessed an electrostatic nature. The bunching of charge in the impulser brings this electrostatic field to a peak in a small instant of time.

Constricting this field volume produces a greatly magnified voltage. Placement of any conductor in the field space alters the field by constricting its shape. When symmetrical conductors of special shape, volume, and resistance are placed in this space, the field is greatly constricted. Because the impulsing electrostatic field is very abrupt, it “snaps” over the conductor from end to end.

Tesla knew that here is where the secret lies. If resistance in the conductor is great enough, the snapping electrostatic force cannot move any charges. It is forced to “grow” over the conductor surface until it discharges at the end point, where greatly magnified voltages are obtained. When the wire diameter is small enough, the wire explodes under electrostatic pressures which exceed those seen in dynamite.

In effect, Tesla had managed to interrupt a high voltage direct current several thousand times per second. In doing so, he had discovered a way to completely separate electrostatic energy from current impulses. Tesla pondered these facts, wondering if it was possible to force the magnification effect beyond the limits of standard electromagnetic transformers. In other words, how high could voltage be raised? Was there a limit to the process?

In order to achieve such enormous voltage levels, he needed a conductive shape which offered so much resistance to charge movement, that all the applied energy would become electrostatic. In effect, Tesla wanted to convert a quantity of supply power into a pure electrostatic voltage. This phenomena suggested that his goal was not impossible.

Tesla extended his idea of the cut copper cylinder to coils. From the viewpoint of electrostatic impulses, flat copper coils appear to be “continuously cut” cylinders. The electrostatic field focuses over the coil as it did with the cylinders, from end to end. A simple magnet coil of specific volume would offer so much resistance that it would be difficult to predict the actual resultant voltage which results without an empirical test.


Constructing several of these, he was ready for the test. When each copper magnet coil was impulsed, Tesla saw tremendous white brushes leaping from their free ends: discharges approaching one million volts! But his supply power was nowhere near these voltages, and the coil was not wrapped in thousands of windings. These previously unexpected voltage magnifications were the result of an energy transformation, one which took electrical power and converted it completely into pressure. Watts into Volts, an unheard thing. It was the key to a new and explosive technology.

Tesla also found that such coils required very thin coil forms. He ceased using cellulose and cardboard forms, preferring “squirrel cage” type forms made of thin end-braced wooden rods. Wire was wound about these cylindrically disposed rods, producing the very best effects. Spacings were also tried between successive coil windings with excellent results. Spaced windings reduced sparking to a minimum.

Tesla remarked that the electrostatic potentials along the coil surface (from end to end) could be as much as ten thousand volts per inch of winding! A ten inch coil of proper volume could produce one hundred thousand volt discharges. In addition, and in confirmation of his suspicions, no current was ever measured at the free terminals of these coils. A “zero coil current” condition! It was simply another paradox which would occupy the academicians for several more argumentative decades.