ELECTRIC ENERGY WITHOUT WIRES 165 



hours, and all in a radius of certainly less than fifty kilometers 

 from the laboratory. Many of them resembled gigantic trees 

 of fire with the trunks up or down. I never saw fire balls, 

 but as a compensation for my disappointment I succeeded 

 later in determining the mode of their formation and pro- 

 ducing them artificially. 



In the latter part of the same month I noticed several 

 times that my instruments were affected stronger by discharges 

 taking place at great distances than by those near by. This 

 puzzled me very much. What was the cause? A number 

 of observations proved that it could not be due to the differ- 

 ences in the intensity of the individual discharges, and I 

 readily ascertained that the phenomenon was not the result 

 of a varying relation between the periods of my receiving 

 circuits and those of the terrestrial disturbances. One night, 

 as I was walking home with an assistant, meditating over 

 these experiences, I was suddenly staggered by a thought. 

 Years ago, when I wrote a chapter of my lecture before the 

 Franklin institute and the National Electric Light association, 

 it had presented itself to me, but I had dismissed it as absurd 

 and impossible. I banished it again. Nevertheless, my 

 instinct was aroused and somehow I felt that I was nearing 

 a great revelation. 



It was on the third of July — the date I shall never forget 

 — ^w^hen I obtained the first decisive experimental evidence 

 of a truth of overwhelming importance for the advancement 

 of humanity. A dense mass of strongly charged clouds 

 gathered in the west and towards the evening a violent storm 

 broke loose which, after spending much of its fury in the 

 mountains, was driven away with great velocity over the 

 plains. Heavy and long persisting arcs formed almost in 

 regular time intervals. My observ^ations were now greatly 

 facilitated and rendered more accurate by the experiences 

 already gained. I was able to handle my instruments quickly 

 and I was prepared. The recording apparatus being properly 

 adjusted, its indications became fainter and fainter with the 

 increasing distance of the storm, until they ceased altogether. 

 I was watching in eager expectation. Surely enough, in a 

 little while the indications again began, grew stronger and 



