Empirical observation had long taught that ordinary capacitor discharges were oscillating currents, spark currents which literally “bounced” between each capacitor plate until their stored energy was wasted away. The high voltage of the dynamo exerted such an intense unidirectional pressure on the densified charges that alternations were impossible. The only possible backrushes were oscillations. In this case, charges surged and stopped in a long series until the supercharge was wasted away. All parameters which forced such oscillations actually limited the supercharge from manifesting its total energetic supply, a condition Tesla strove to eliminate. Indeed he spent an excessive time developing various means to block every “backrush” and other complex current echo which might forced the supercharge to prematurely waste its dense energy. Here was an effect demanding a single unidirectional super pulse. With both the oscillations and alternations eliminated, new and strange effects began making their appearance. These powerful and penetrating phenomena were never observed when working with high frequency alternations.
The sudden quick closure of the switch now brought a penetrating shockwave throughout the laboratory, one which could be felt both as a sharp pressure and a penetrating electrical irritation. A “sting”. Face and hands were especially sensitive to the explosive Shockwaves, which also produced a curious “stinging” effect at close range. Tesla believed that material particles approaching the vapor state were literally thrust out of the wires in all directions. In order to better study these effects, he poised himself behind a glass shield and resumed the study. Despite the shield, both Shockwaves and stinging effects were felt by the now mystified Tesla. This anomaly provoked a curiosity of the very deepest kind, for such a thing was never before observed. More powerful and penetrating than the mere electrostatic charging of metals, this phenomenon literally propelled high voltage charge out into the surrounding space where it was felt as a stinging sensation. The stings lasting for a small fraction of a second, the instant of switch closure. But Tesla believed that these strange effects were a simple effect of ionized Shockwaves in the air, rather like a strongly ionized thunderclap.
Tesla devised a new series of experiments to measure the shockwave pressure from a greater distance. He required an automatic “trip switch”. With this properly arranged, a more controlled and repetitious triggering of the effect was possible. In addition, this arrangement permitted distant observations which might cast more light on the shied-permeating phenomenon. Controlling the speed of the high voltage dynamo controlled the voltage. With these components properly adjusted, Tesla was able to walk around his large gallery spaces and make observations. Wishing also to avoid the continuous pressure barrage and its stinging sparks, Tesla shielded himself with several materials. The arrangement of rapidly interrupted high voltage direct currents resulted in the radiation of stinging rays which could be felt at great distances from their super-sparking source. In fact, Tesla felt the stings right through the shields! Whatever had been released from the wires during the instant of switch closure, successfully penetrated the shields of glass and of copper. It made no difference, the effect permeated each substance as if the shield were not there at all. Here was an electrical effect which communicated directly through space without material connections. Radiant electricity!
In these several new observations, the phenomenon was violating electrostatic charge principles experimentally established by Faraday. Projected electrostatic charges normally spread out over the surface of metallic shield, they do not penetrate metal. This effect had certain very non-electrical characteristics. Tesla was truly mystified by this strange new phenomenon, and searched the literature for references to its characteristics. No such reference was found, except in the surreptitious observations of two experimenters. In one case, Joseph Henry observed the magnetization of steel needles by a heavy spark discharge. The extraordinary feature of this observation (1842) lay in the fact that the Leyden Jar, whose spark apparently produced the magnetizations, stood on the upper floor of an otherwise electrically impervious building. Brick walls, thick oak doors, heavy stone and iron flooring, tin ceilings. Moreover, the steel needles were housed in a vault in the cellar. How did the spark affect such a change through such a natural barrier? Dr. Henry believed that the spark had released special “light-like rays”, and these were the penetrating agencies responsible for the magnetizations.
A second such account (1872) occurred in a high school building in Philadelphia. Elihu Thomson, a physics instructor, sought to make the sparks of a large Ruhmkorrf Spark Coil more visible for his next lecture. Attaching one pole of the coil to a cold water pipe, and reactivating the coil, Thomson was thrilled to find that the nature of the spark had changed from blue to white. Wishing to amplify this effect, Thomson attached the other pole to a large metal tabletop. Again reactivating the coil produced a shrieking silver-white spark, entirely visible to any who sat in the last row. Wishing to show this to a colleague, Edwin Houston, Thomson made for the door and was abruptly stopped. Touching the brass knob on the otherwise insulated oak door, Thomson received an unexpected sizzling shock. Turning off the Ruhmkorrf Coil, Thomson found it possible to stop the effect. Calling for Edwin, he summarized what had occurred. Then turning the unit back on again, the stinging charge effects returned. The two gendemen ran throughout the huge stone, oak, and iron building with insulated metal objects now. Each touch of a penknife or screwdriver to anything metallic, however distant from the coil or insulated from the floor, produced long and continuous white sparks. The account was written up as a short article in Scientific American later in the same year.
In studying each of these two prior observations, events each separated by some thirty’ years, Tesla perceived an essential unity with that of his own discover)’. Each observation was perhaps a slight variant of the very same phenomenon. Somehow accidentally, each experimenter had managed to produce the explosive supercharging effect. In the case of Dr. Henry, the explosive bursts occurred in a single flash, electrostatic machines being used to accumulate the initial charge. The second case was peculiar, since it evidenced the sustained and continuous production of super-charging effects. The effect was rare because it obviously required very stringent electrical parameters. Tesla deduced this from the simple fact that the effect was so infrequently observed by experimenters the world over. In addition, he was quick to remark concerning the anomalous attributes attached to the phenomenon. Tesla knew that, despite the extremely penetrating effects in each case, he had secured the only means for achieving the “complete” and maximum manifestation of supercharging. His was an apparatus with no equal, capable of releasing an aspect of the electrostatic field which others very apparendy had not.
- PROLOGUE — Symbols and Models
- CHAPTER 2