Nikola Tesla Books
one of the popular thirty thousand institutions of this great city, where a delicious twelve per cent beverage was served, which can now be had only by making a trip to the poor and devastated countries of Europe. The attendance was large and not over-distinguished and a matter was discussed which gave me an admirable opening for the careless remark, "This is what I said when I jumped off the bridge." No sooner had I uttered these words, than I felt like the companion of Timothens, in the poem of Schiller. In an instant there was pandemonium and a dozen voices cried, "It is Brodie!" I threw a quarter on the counter and bolted for the door, but the crowd was at my heels with yells, "Stop, Steeve!", which must have been misunderstood, for many persons tried to hold me up as I ran frantically for my haven of refuge. By darting around corners I fortunately managed, through the medium of a fire escape, to reach the laboratory, where I threw off my coat, camouflaged myself as a hard-working blacksmith and started the forge. But these precautions proved unnecessary, as I had eluded my pursuers. For many years afterward, at night, when imagination turns into spectres the trifling troubles of the day, I often thought, as I tossed on the bed, what my fate would have been, had the mob caught me and found out that I was not Steve Brodie! Now the engineer who lately gave an account before a technical body of a novel remedy against statics based on a "heretofore unknown law of nature," seems to have been as reckless as myself when he contended that these disturbances propagate up and down, while those of a transmitter proceed along the earth. It would mean that a condenser as this globe, with its gaseous envelope, could be charged and discharged in a manner quite contrary to the fundamental teachings propounded in every elemental text book of physics. Such a supposition would have been condemned as erroneous, even in Franklin's time, for the facts bearing on this were then well known and the identity between atmospheric electricity and that developed by machines was fully established. Obviously, natural and artificial disturbances propagate through the earth and the air in exactly the same way, and both set up electromotive forces in the horizontal, as well as vertical sense. Interference can not be overcome by any such methods as were proposed. The truth is this: In the air the potential increases at the rate of about fifty volts per foot of elevation, owing to which there may be a difference of pressure amounting to twenty, or even forty thousand volts between the upper and lower ends of the antenna. The masses of the charged atmosphere are constantly in motion and give up electricity to the conductor, not continuously, but rather disruptively, this producing a grinding noise in a sensitive telephonic receiver. The higher the terminal and the greater the space encompast by the wires, the more pronounced is the effect, but it must be understood that it is purely local and has little to do with the real trouble. In 1900, while perfecting my wireless system, one form of apparatus compressed four antennae. These were carefully calibrated in the same frequency and connected in multiple with the object of magnifying the action in receiving from any direction. When I desired to ascertain the origin of the transmitted impulse, each diagonally situated pair was put in series with a primary coil energising the detector circuit. In the former case, the sound was loud in the telephone; in the latter it ceased, as expected, - the two antennae neutralising each other, but the true statics manifested themselves in both instances and I had to devise special preventives embodying different principles. By employing receivers connected to two points of the ground, as suggested by me long ago, this trouble caused by the charged air, which is very serious in the structures as now built, is nullified and besides, the liability of all kinds of interference is reduced to about one-half because of the directional character of the circuit. This was perfectly self-evident, but The Strange Life of Nikla Tesla 33
